Gaussian elimination: Difference between revisions
add output of the java code, add output of the scala code
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{{out}}
<pre>1.00, 0.00, 0.00, 4.00</pre>
=={{header|EasyLang}}==
<syntaxhighlight>
proc gauss_elim . a[][] b[] x[] .
n = len a[][]
for i to n
maxr = i
maxv = abs a[i][i]
for j = i + 1 to n
if abs a[j][i] > maxv
maxr = j
maxv = abs a[j][i]
.
.
if maxr <> i
swap a[maxr][] a[i][]
swap b[maxr] b[i]
.
for j = i + 1 to n
f = a[j][i] / a[i][i]
for k = i to n
a[j][k] -= f * a[i][k]
.
b[j] -= f * b[i]
.
.
x[] = [ ]
len x[] n
for i = n downto 1
rhs = b[i]
for j = i + 1 to n
rhs -= a[i][j] * x[j]
.
x[i] = rhs / a[i][i]
.
.
a[][] = [ [ 1.00 0.00 0.00 0.00 0.00 0.00 ] [ 1.00 0.63 0.39 0.25 0.16 0.10 ] [ 1.00 1.26 1.58 1.98 2.49 3.13 ] [ 1.00 1.88 3.55 6.70 12.62 23.80 ] [ 1.00 2.51 6.32 15.88 39.90 100.28 ] [ 1.00 3.14 9.87 31.01 97.41 306.02 ] ]
b[] = [ -0.01 0.61 0.91 0.99 0.60 0.02 ]
gauss_elim a[][] b[] x[]
print x[]
</syntaxhighlight>
=={{header|F_Sharp|F#}}==
Line 3,883 ⟶ 3,924:
}
}</syntaxhighlight>
{{out}}
<pre>
det: 780.0
0.09750000 0.0000e+00
0.11000000 0.0000e+00
0.12916667 0.0000e+00
0.12333333 1.3878e-17
0.17750000 2.7756e-17
</pre>
=={{header|JavaScript}}==
Line 6,447 ⟶ 6,498:
}
</syntaxhighlight>
=={{header|Scala}}==
{{trans|Java}}
<syntaxhighlight lang="Scala">
object GaussianElimination {
def solve(a: Array[Array[Double]], b: Array[Array[Double]]): Double = {
if (a == null || b == null || a.length == 0 || b.length == 0) {
throw new IllegalArgumentException("Invalid dimensions")
}
val n = b.length
val p = b(0).length
if (a.length != n || a(0).length != n) {
throw new IllegalArgumentException("Invalid dimensions")
}
var det = 1.0
for (i <- 0 until n - 1) {
var k = i
for (j <- i + 1 until n) {
if (Math.abs(a(j)(i)) > Math.abs(a(k)(i))) {
k = j
}
}
if (k != i) {
det = -det
for (j <- i until n) {
val s = a(i)(j)
a(i)(j) = a(k)(j)
a(k)(j) = s
}
for (j <- 0 until p) {
val s = b(i)(j)
b(i)(j) = b(k)(j)
b(k)(j) = s
}
}
for (j <- i + 1 until n) {
val s = a(j)(i) / a(i)(i)
for (k <- i + 1 until n) {
a(j)(k) -= s * a(i)(k)
}
for (k <- 0 until p) {
b(j)(k) -= s * b(i)(k)
}
}
}
for (i <- n - 1 to 0 by -1) {
for (j <- i + 1 until n) {
val s = a(i)(j)
for (k <- 0 until p) {
b(i)(k) -= s * b(j)(k)
}
}
val s = a(i)(i)
det *= s
for (k <- 0 until p) {
b(i)(k) /= s
}
}
det
}
def main(args: Array[String]): Unit = {
val a = Array(
Array(4.0, 1.0, 0.0, 0.0, 0.0),
Array(1.0, 4.0, 1.0, 0.0, 0.0),
Array(0.0, 1.0, 4.0, 1.0, 0.0),
Array(0.0, 0.0, 1.0, 4.0, 1.0),
Array(0.0, 0.0, 0.0, 1.0, 4.0)
)
val b = Array(
Array(1.0 / 2.0),
Array(2.0 / 3.0),
Array(3.0 / 4.0),
Array(4.0 / 5.0),
Array(5.0 / 6.0)
)
val x = Array(39.0 / 400.0, 11.0 / 100.0, 31.0 / 240.0, 37.0 / 300.0, 71.0 / 400.0)
println("det: " + solve(a, b))
for (i <- 0 until 5) {
printf("%12.8f %12.4e\n", b(i)(0), b(i)(0) - x(i))
}
}
}
</syntaxhighlight>
{{out}}
<pre>
det: 780.0
0.09750000 0.0000e+00
0.11000000 0.0000e+00
0.12916667 0.0000e+00
0.12333333 1.3878e-17
0.17750000 2.7756e-17
</pre>
=={{header|Sidef}}==
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