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Geometric algebra (view source)

Revision as of 20:21, 18 January 2022

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→‎{{header|Phix}}: added syntax colouring, marked p2js compatible
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=={{header|Phix}}==
{{trans|Go}}
<!--<lang Phix>function bitCount(integer iphixonline)-->
<span style="color: #008080;">with</span> <span style="color: #008080;">javascript_semantics</span>
return sum(sq_eq(sprintf("%b",i),'1')) -- (idea cribbed from Python)
<span style="color: #008080;">function</span> <span style="color: #000000;">bitCount</span><span style="color: #0000FF;">(</span><span style="color: #004080;">integer</span> <span style="color: #000000;">i</span><span style="color: #0000FF;">)</span>
end function
<span style="color: #008080;">return</span> <span style="color: #7060A8;">sum</span><span style="color: #0000FF;">(</span><span style="color: #7060A8;">sq_eq</span><span style="color: #0000FF;">(</span><span style="color: #7060A8;">sprintf</span><span style="color: #0000FF;">(</span><span style="color: #008000;">"%b"</span><span style="color: #0000FF;">,</span><span style="color: #000000;">i</span><span style="color: #0000FF;">),</span><span style="color: #008000;">'1'</span><span style="color: #0000FF;">))</span> <span style="color: #000080;font-style:italic;">-- (idea cribbed from Python)</span>
<span style="color: #008080;">end</span> <span style="color: #008080;">function</span>
function reorderingSign(integer i, j)
i = floor(i/2)
integer tot := 0
while i!=0 do
tot += bitCount(and_bits(i,j))
i = floor(i/2)
end while
return iff(and_bits(tot,1)==0 ? 1 : -1)
end function
function add(sequence a, b)
return sq_add(a,b)
end function
 
function mul(sequence a, b)
sequence result = repeat(0,32)
for i=1 to length(a) do
if a[i]!=0 then
for j=1 to length(b) do
if b[j]!=0 then
atom s := reorderingSign(i-1, j-1) * a[i] * b[j]
integer k = xor_bits(i-1,j-1)+1
result[k] += s
end if
end for
end if
end for
return result
end function
function cdot(sequence a, b)
return mul({0.5}, add(mul(a, b), mul(b, a)))
end function
function e(integer n)
if n>4 then crash("n must be less than 5") end if
sequence result = repeat(0,32)
result[power(2,n)+1] = 1.0
return result
end function
--function neg(sequence x) -- (not actually used here)
-- return mul({-1}, x)
--end function
<span style="color: #008080;">function</span> <span style="color: #000000;">reorderingSign</span><span style="color: #0000FF;">(</span><span style="color: #004080;">integer</span> <span style="color: #000000;">i</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">j</span><span style="color: #0000FF;">)</span>
function randomVector()
<span style="color: #000000;">i</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">floor</span><span style="color: #0000FF;">(</span><span style="color: #000000;">i</span><span style="color: #0000FF;">/</span><span style="color: #000000;">2</span><span style="color: #0000FF;">)</span>
sequence result = repeat(0,32)
<span style="color: #004080;">integer</span> <span style="color: #000000;">tot</span> <span style="color: #0000FF;">:=</span> <span style="color: #000000;">0</span>
for i=0 to 4 do
<span style="color: #008080;">while</span> <span style="color: #000000;">i</span><span style="color: #0000FF;">!=</span><span style="color: #000000;">0</span> <span style="color: #008080;">do</span>
result = add(result, mul({rnd()}, e(i)))
<span style="color: #000000;">tot</span> <span style="color: #0000FF;">+=</span> <span style="color: #000000;">bitCount</span><span style="color: #0000FF;">(</span><span style="color: #7060A8;">and_bits</span><span style="color: #0000FF;">(</span><span style="color: #000000;">i</span><span style="color: #0000FF;">,</span><span style="color: #000000;">j</span><span style="color: #0000FF;">))</span>
end for
<span style="color: #000000;">i</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">floor</span><span style="color: #0000FF;">(</span><span style="color: #000000;">i</span><span style="color: #0000FF;">/</span><span style="color: #000000;">2</span><span style="color: #0000FF;">)</span>
return result
<span style="color: #008080;">end</span> <span style="color: #008080;">while</span>
end function
<span style="color: #008080;">return</span> <span style="color: #008080;">iff</span><span style="color: #0000FF;">(</span><span style="color: #7060A8;">and_bits</span><span style="color: #0000FF;">(</span><span style="color: #000000;">tot</span><span style="color: #0000FF;">,</span><span style="color: #000000;">1</span><span style="color: #0000FF;">)==</span><span style="color: #000000;">0</span> <span style="color: #0000FF;">?</span> <span style="color: #000000;">1</span> <span style="color: #0000FF;">:</span> <span style="color: #0000FF;">-</span><span style="color: #000000;">1</span><span style="color: #0000FF;">)</span>
<span style="color: #008080;">end</span> <span style="color: #008080;">function</span>
function randomMultiVector()
sequence result = repeat(0, 32)
<span style="color: #008080;">function</span> <span style="color: #000000;">add</span><span style="color: #0000FF;">(</span><span style="color: #004080;">sequence</span> <span style="color: #000000;">a</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">b</span><span style="color: #0000FF;">)</span>
for i=1 to 32 do
<span style="color: #008080;">return</span> <span style="color: #7060A8;">sq_add</span><span style="color: #0000FF;">(</span><span style="color: #000000;">a</span><span style="color: #0000FF;">,</span><span style="color: #000000;">b</span><span style="color: #0000FF;">)</span>
result[i] = rnd()
<span style="color: #008080;">end</span> <span style="color: #008080;">function</span>
end for
return result
<span style="color: #008080;">function</span> <span style="color: #000000;">mul</span><span style="color: #0000FF;">(</span><span style="color: #004080;">sequence</span> <span style="color: #000000;">a</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">b</span><span style="color: #0000FF;">)</span>
end function
<span style="color: #004080;">sequence</span> <span style="color: #000000;">result</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">repeat</span><span style="color: #0000FF;">(</span><span style="color: #000000;">0</span><span style="color: #0000FF;">,</span><span style="color: #000000;">32</span><span style="color: #0000FF;">)</span>
 
<span style="color: #008080;">for</span> <span style="color: #000000;">i</span><span style="color: #0000FF;">=</span><span style="color: #000000;">1</span> <span style="color: #008080;">to</span> <span style="color: #7060A8;">length</span><span style="color: #0000FF;">(</span><span style="color: #000000;">a</span><span style="color: #0000FF;">)</span> <span style="color: #008080;">do</span>
for i=0 to 4 do
<span style="color: #008080;">if</span> <span style="color: #000000;">a</span><span style="color: #0000FF;">[</span><span style="color: #000000;">i</span><span style="color: #0000FF;">]!=</span><span style="color: #000000;">0</span> <span style="color: #008080;">then</span>
for j=0 to 4 do
<span style="color: #008080;">for</span> <span style="color: #000000;">j</span><span style="color: #0000FF;">=</span><span style="color: #000000;">1</span> <span style="color: #008080;">to</span> <span style="color: #7060A8;">length</span><span style="color: #0000FF;">(</span><span style="color: #000000;">b</span><span style="color: #0000FF;">)</span> <span style="color: #008080;">do</span>
if i < j then
<span style="color: #008080;">if</span> <span style="color: #000000;">b</span><span style="color: #0000FF;">[</span><span style="color: #000000;">j</span><span style="color: #0000FF;">]!=</span><span style="color: #000000;">0</span> <span style="color: #008080;">then</span>
if cdot(e(i), e(j))[1] != 0 then
<span style="color: #004080;">atom</span> <span style="color: #000000;">s</span> <span style="color: #0000FF;">:=</span> <span style="color: #000000;">reorderingSign</span><span style="color: #0000FF;">(</span><span style="color: #000000;">i</span><span style="color: #0000FF;">-</span><span style="color: #000000;">1</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">j</span><span style="color: #0000FF;">-</span><span style="color: #000000;">1</span><span style="color: #0000FF;">)</span> <span style="color: #0000FF;">*</span> <span style="color: #000000;">a</span><span style="color: #0000FF;">[</span><span style="color: #000000;">i</span><span style="color: #0000FF;">]</span> <span style="color: #0000FF;">*</span> <span style="color: #000000;">b</span><span style="color: #0000FF;">[</span><span style="color: #000000;">j</span><span style="color: #0000FF;">]</span>
crash("Unexpected non-null scalar product.")
<span style="color: #004080;">integer</span> <span style="color: #000000;">k</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">xor_bits</span><span style="color: #0000FF;">(</span><span style="color: #000000;">i</span><span style="color: #0000FF;">-</span><span style="color: #000000;">1</span><span style="color: #0000FF;">,</span><span style="color: #000000;">j</span><span style="color: #0000FF;">-</span><span style="color: #000000;">1</span><span style="color: #0000FF;">)+</span><span style="color: #000000;">1</span>
end if
<span style="color: #000000;">result</span><span style="color: #0000FF;">[</span><span style="color: #000000;">k</span><span style="color: #0000FF;">]</span> <span style="color: #0000FF;">+=</span> <span style="color: #000000;">s</span>
elsif i == j then
<span style="color: #008080;">end</span> <span style="color: #008080;">if</span>
if cdot(e(i), e(j))[1] == 0 then
<span style="color: crash(#008080;"Unexpected>end</span> null<span scalarstyle="color: product.#008080;")>for</span>
<span style="color: #008080;">end</span> <span style="color: #008080;">if</span>
end if
<span style="color: #008080;">end</span> <span style="color: #008080;">for</span>
end if
<span style="color: #008080;">return</span> <span style="color: #000000;">result</span>
end for
<span style="color: #008080;">end</span> <span style="color: #008080;">function</span>
end for
<span style="color: #008080;">function</span> <span style="color: #000000;">cdot</span><span style="color: #0000FF;">(</span><span style="color: #004080;">sequence</span> <span style="color: #000000;">a</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">b</span><span style="color: #0000FF;">)</span>
sequence a := randomMultiVector(),
<span style="color: #008080;">return</span> <span style="color: #000000;">mul</span><span style="color: #0000FF;">({</span><span style="color: #000000;">0.5</span><span style="color: #0000FF;">},</span> <span style="color: #000000;">add</span><span style="color: #0000FF;">(</span><span style="color: #000000;">mul</span><span style="color: #0000FF;">(</span><span style="color: #000000;">a</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">b</span><span style="color: #0000FF;">),</span> <span style="color: #000000;">mul</span><span style="color: #0000FF;">(</span><span style="color: #000000;">b</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">a</span><span style="color: #0000FF;">)))</span>
b := randomMultiVector(),
<span style="color: #008080;">end</span> <span style="color: #008080;">function</span>
c := randomMultiVector(),
x := randomVector(),
<span style="color: #008080;">function</span> <span style="color: #000000;">e</span><span style="color: #0000FF;">(</span><span style="color: #004080;">integer</span> <span style="color: #000000;">n</span><span style="color: #0000FF;">)</span>
xsq = mul(x, x)
<span style="color: #008080;">if</span> <span style="color: #000000;">n</span><span style="color: #0000FF;">></span><span style="color: #000000;">4</span> <span style="color: #008080;">then</span> <span style="color: #7060A8;">crash</span><span style="color: #0000FF;">(</span><span style="color: #008000;">"n must be less than 5"</span><span style="color: #0000FF;">)</span> <span style="color: #008080;">end</span> <span style="color: #008080;">if</span>
 
<span style="color: #004080;">sequence</span> <span style="color: #000000;">result</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">repeat</span><span style="color: #0000FF;">(</span><span style="color: #000000;">0</span><span style="color: #0000FF;">,</span><span style="color: #000000;">32</span><span style="color: #0000FF;">)</span>
procedure test(string txt, sequence a, b)
<span style="color: #000000;">result</span><span style="color: #0000FF;">[</span><span style="color: #7060A8;">power</span><span style="color: #0000FF;">(</span><span style="color: #000000;">2</span><span style="color: #0000FF;">,</span><span style="color: #000000;">n</span><span style="color: #0000FF;">)+</span><span style="color: #000000;">1</span><span style="color: #0000FF;">]</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">1.0</span>
-- bool eq = (a==b) -- no!
<span style="color: #008080;">return</span> <span style="color: #000000;">result</span>
bool eq = (sprint(a)==sprint(b)) -- ok!
<span style="color: #008080;">end</span> <span style="color: #008080;">function</span>
printf(1,"%-20s: %s\n",{txt,iff(eq?"true","false")})
end procedure
<span style="color: #000080;font-style:italic;">--function neg(sequence x) -- (not actually used here)
test("(ab)c -- == a(bc)",return mul(mul(a{-1}, bx), c),
--end function</span>
mul(a, mul(b, c)))
 
<span style="color: #008080;">function</span> <span style="color: #000000;">randomVector</span><span style="color: #0000FF;">()</span>
test("a(b + c) == ab + ac",mul(a, add(b, c)),
<span style="color: #004080;">sequence</span> <span style="color: #000000;">result</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">repeat</span><span style="color: #0000FF;">(</span><span style="color: #000000;">0</span><span style="color: #0000FF;">,</span><span style="color: #000000;">32</span><span style="color: #0000FF;">)</span>
add(mul(a, b), mul(a, c)))
<span style="color: #008080;">for</span> <span style="color: #000000;">i</span><span style="color: #0000FF;">=</span><span style="color: #000000;">0</span> <span style="color: #008080;">to</span> <span style="color: #000000;">4</span> <span style="color: #008080;">do</span>
<span style="color: #000000;">result</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">add</span><span style="color: #0000FF;">(</span><span style="color: #000000;">result</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">mul</span><span style="color: #0000FF;">({</span><span style="color: #7060A8;">rnd</span><span style="color: #0000FF;">()},</span> <span style="color: #000000;">e</span><span style="color: #0000FF;">(</span><span style="color: #000000;">i</span><span style="color: #0000FF;">)))</span>
test("(a + b)c == ac + bc",mul(add(a, b), c),
<span style="color: #008080;">end</span> <span style="color: #008080;">for</span>
add(mul(a, c), mul(b, c)))
<span style="color: #008080;">return</span> <span style="color: #000000;">result</span>
<span style="color: #008080;">end</span> <span style="color: #008080;">function</span>
test("x^2 is real",xsq,xsq[1]&repeat(0,31))</lang>
<span style="color: #008080;">function</span> <span style="color: #000000;">randomMultiVector</span><span style="color: #0000FF;">()</span>
<span style="color: #004080;">sequence</span> <span style="color: #000000;">result</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">repeat</span><span style="color: #0000FF;">(</span><span style="color: #000000;">0</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">32</span><span style="color: #0000FF;">)</span>
<span style="color: #008080;">for</span> <span style="color: #000000;">i</span><span style="color: #0000FF;">=</span><span style="color: #000000;">1</span> <span style="color: #008080;">to</span> <span style="color: #000000;">32</span> <span style="color: #008080;">do</span>
<span style="color: #000000;">result</span><span style="color: #0000FF;">[</span><span style="color: #000000;">i</span><span style="color: #0000FF;">]</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">rnd</span><span style="color: #0000FF;">()</span>
<span style="color: #008080;">end</span> <span style="color: #008080;">for</span>
<span style="color: #008080;">return</span> <span style="color: #000000;">result</span>
<span style="color: #008080;">end</span> <span style="color: #008080;">function</span>
<span style="color: #008080;">for</span> <span style="color: #000000;">i</span><span style="color: #0000FF;">=</span><span style="color: #000000;">0</span> <span style="color: #008080;">to</span> <span style="color: #000000;">4</span> <span style="color: #008080;">do</span>
<span style="color: #008080;">for</span> <span style="color: #000000;">j</span><span style="color: #0000FF;">=</span><span style="color: #000000;">0</span> <span style="color: #008080;">to</span> <span style="color: #000000;">4</span> <span style="color: #008080;">do</span>
<span style="color: #008080;">if</span> <span style="color: #000000;">i</span> <span style="color: #0000FF;"><</span> <span style="color: #000000;">j</span> <span style="color: #008080;">then</span>
<span style="color: #008080;">if</span> <span style="color: #000000;">cdot</span><span style="color: #0000FF;">(</span><span style="color: #000000;">e</span><span style="color: #0000FF;">(</span><span style="color: #000000;">i</span><span style="color: #0000FF;">),</span> <span style="color: #000000;">e</span><span style="color: #0000FF;">(</span><span style="color: #000000;">j</span><span style="color: #0000FF;">))[</span><span style="color: #000000;">1</span><span style="color: #0000FF;">]</span> <span style="color: #0000FF;">!=</span> <span style="color: #000000;">0</span> <span style="color: #008080;">then</span>
<span style="color: #7060A8;">crash</span><span style="color: #0000FF;">(</span><span style="color: #008000;">"Unexpected non-null scalar product."</span><span style="color: #0000FF;">)</span>
<span style="color: #008080;">end</span> <span style="color: #008080;">if</span>
<span style="color: #008080;">elsif</span> <span style="color: #000000;">i</span> <span style="color: #0000FF;">==</span> <span style="color: #000000;">j</span> <span style="color: #008080;">then</span>
<span style="color: #008080;">if</span> <span style="color: #000000;">cdot</span><span style="color: #0000FF;">(</span><span style="color: #000000;">e</span><span style="color: #0000FF;">(</span><span style="color: #000000;">i</span><span style="color: #0000FF;">),</span> <span style="color: #000000;">e</span><span style="color: #0000FF;">(</span><span style="color: #000000;">j</span><span style="color: #0000FF;">))[</span><span style="color: #000000;">1</span><span style="color: #0000FF;">]</span> <span style="color: #0000FF;">==</span> <span style="color: #000000;">0</span> <span style="color: #008080;">then</span>
<span style="color: #7060A8;">crash</span><span style="color: #0000FF;">(</span><span style="color: #008000;">"Unexpected null scalar product."</span><span style="color: #0000FF;">)</span>
<span style="color: #008080;">end</span> <span style="color: #008080;">if</span>
<span style="color: #008080;">end</span> <span style="color: #008080;">if</span>
<span style="color: #008080;">end</span> <span style="color: #008080;">for</span>
<span style="color: #008080;">end</span> <span style="color: #008080;">for</span>
<span style="color: #004080;">sequence</span> <span style="color: #000000;">a</span> <span style="color: #0000FF;">:=</span> <span style="color: #000000;">randomMultiVector</span><span style="color: #0000FF;">(),</span>
<span style="color: #000000;">b</span> <span style="color: #0000FF;">:=</span> <span style="color: #000000;">randomMultiVector</span><span style="color: #0000FF;">(),</span>
<span style="color: #000000;">c</span> <span style="color: #0000FF;">:=</span> <span style="color: #000000;">randomMultiVector</span><span style="color: #0000FF;">(),</span>
<span style="color: #000000;">x</span> <span style="color: #0000FF;">:=</span> <span style="color: #000000;">randomVector</span><span style="color: #0000FF;">(),</span>
<span style="color: #000000;">xsq</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">mul</span><span style="color: #0000FF;">(</span><span style="color: #000000;">x</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">x</span><span style="color: #0000FF;">)</span>
<span style="color: #008080;">procedure</span> <span style="color: #000000;">test</span><span style="color: #0000FF;">(</span><span style="color: #004080;">string</span> <span style="color: #000000;">txt</span><span style="color: #0000FF;">,</span> <span style="color: #004080;">sequence</span> <span style="color: #000000;">a</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">b</span><span style="color: #0000FF;">)</span>
<span style="color: #000080;font-style:italic;">-- bool eq = (a==b) -- no!</span>
<span style="color: #004080;">bool</span> <span style="color: #000000;">eq</span> <span style="color: #0000FF;">=</span> <span style="color: #0000FF;">(</span><span style="color: #7060A8;">sprint</span><span style="color: #0000FF;">(</span><span style="color: #000000;">a</span><span style="color: #0000FF;">)==</span><span style="color: #7060A8;">sprint</span><span style="color: #0000FF;">(</span><span style="color: #000000;">b</span><span style="color: #0000FF;">))</span> <span style="color: #000080;font-style:italic;">-- ok!</span>
<span style="color: #7060A8;">printf</span><span style="color: #0000FF;">(</span><span style="color: #000000;">1</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"%-20s: %s\n"</span><span style="color: #0000FF;">,{</span><span style="color: #000000;">txt</span><span style="color: #0000FF;">,</span><span style="color: #008080;">iff</span><span style="color: #0000FF;">(</span><span style="color: #000000;">eq</span><span style="color: #0000FF;">?</span><span style="color: #008000;">"true"</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"false"</span><span style="color: #0000FF;">)})</span>
<span style="color: #008080;">end</span> <span style="color: #008080;">procedure</span>
<span style="color: #000000;">test</span><span style="color: #0000FF;">(</span><span style="color: #008000;">"(ab)c == a(bc)"</span><span style="color: #0000FF;">,</span><span style="color: #000000;">mul</span><span style="color: #0000FF;">(</span><span style="color: #000000;">mul</span><span style="color: #0000FF;">(</span><span style="color: #000000;">a</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">b</span><span style="color: #0000FF;">),</span> <span style="color: #000000;">c</span><span style="color: #0000FF;">),</span>
<span style="color: #000000;">mul</span><span style="color: #0000FF;">(</span><span style="color: #000000;">a</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">mul</span><span style="color: #0000FF;">(</span><span style="color: #000000;">b</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">c</span><span style="color: #0000FF;">)))</span>
<span style="color: #000000;">test</span><span style="color: #0000FF;">(</span><span style="color: #008000;">"a(b + c) == ab + ac"</span><span style="color: #0000FF;">,</span><span style="color: #000000;">mul</span><span style="color: #0000FF;">(</span><span style="color: #000000;">a</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">add</span><span style="color: #0000FF;">(</span><span style="color: #000000;">b</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">c</span><span style="color: #0000FF;">)),</span>
<span style="color: #000000;">add</span><span style="color: #0000FF;">(</span><span style="color: #000000;">mul</span><span style="color: #0000FF;">(</span><span style="color: #000000;">a</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">b</span><span style="color: #0000FF;">),</span> <span style="color: #000000;">mul</span><span style="color: #0000FF;">(</span><span style="color: #000000;">a</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">c</span><span style="color: #0000FF;">)))</span>
<span style="color: #000000;">test</span><span style="color: #0000FF;">(</span><span style="color: #008000;">"(a + b)c == ac + bc"</span><span style="color: #0000FF;">,</span><span style="color: #000000;">mul</span><span style="color: #0000FF;">(</span><span style="color: #000000;">add</span><span style="color: #0000FF;">(</span><span style="color: #000000;">a</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">b</span><span style="color: #0000FF;">),</span> <span style="color: #000000;">c</span><span style="color: #0000FF;">),</span>
<span style="color: #000000;">add</span><span style="color: #0000FF;">(</span><span style="color: #000000;">mul</span><span style="color: #0000FF;">(</span><span style="color: #000000;">a</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">c</span><span style="color: #0000FF;">),</span> <span style="color: #000000;">mul</span><span style="color: #0000FF;">(</span><span style="color: #000000;">b</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">c</span><span style="color: #0000FF;">)))</span>
<span style="color: #000000;">test</span><span style="color: #0000FF;">(</span><span style="color: #008000;">"x^2 is real"</span><span style="color: #0000FF;">,</span><span style="color: #000000;">xsq</span><span style="color: #0000FF;">,</span><span style="color: #000000;">xsq</span><span style="color: #0000FF;">[</span><span style="color: #000000;">1</span><span style="color: #0000FF;">]&</span><span style="color: #7060A8;">repeat</span><span style="color: #0000FF;">(</span><span style="color: #000000;">0</span><span style="color: #0000FF;">,</span><span style="color: #000000;">31</span><span style="color: #0000FF;">))</span>
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{{out}}
Note the comparison of string representations of floats, rather than the floats themselves. That effectively ensures they
Petelomax
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edits

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