LU decomposition: Difference between revisions
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→Tcl: Added implementation |
m →{{header|Tcl}}: Smarten up |
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=={{header|Tcl}}==
<lang tcl>package require Tcl 8.5
namespace eval matrix {
namespace path {::tcl::mathfunc ::tcl::mathop}
proc I {order} {▼
# Construct an identity matrix of the given size
set m [lrepeat $order [lrepeat $order 0]]
for {set i 0} {$i < $order} {incr i} {
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return $m
}
# Produce the pivot matrix for a given matrix
proc pivotize {matrix} {
set n [llength $matrix]
set p [
for {set j 0} {$j < $n} {incr j} {
set max [lindex $matrix $j $j]
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}
if {$j != $row} {
# Row swap inlined; too trivial to have separate procedure
set tmp [lindex $p $j]
lset p $j [lindex $p $row]
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}
#
proc luDecompose {A} {
set n [llength $A]
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return $s
}
}</lang>
Support code:
<lang
# Get the size of a matrix; assumes that all rows are the same length, which
# is a basic well-formed-ness condition...
proc size {m} {
set rows [llength $m]
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return [list $rows $cols]
}
# Matrix multiplication implementation
proc multiply {a b} {
lassign [size $a] a_rows a_cols
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}
# Pretty printer for matrices
set max [Widest $matrix $fmt]▼
lassign [size $matrix] rows cols▼
foreach val $row width $max {
puts -nonewline [format "%*s " $width [format $fmt $val]]▼
}▼
puts ""▼
}▼
}▼
proc Widest {m fmt} {
lassign [size $m] rows cols
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return $max
}
}</lang>
▲ proc print {matrix {fmt "%s"}} {
Demonstrating:
▲ set max [Widest $matrix $fmt]
<lang tcl># This does the decomposition and prints it out nicely
▲ lassign [size $matrix] rows cols
▲ foreach row $matrix {
▲ foreach val $row width $max {
▲ puts -nonewline [format "%*s " $width [format $fmt $val]]
▲ }
▲ puts ""
▲ }
▲ }
proc demo {A} {
lassign [matrix::luDecompose $A] L U P
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puts "================================="
demo {{11 9 24 2} {1 5 2 6} {3 17 18 1} {2 5 7 1}}</lang>
Output:
<pre>
A:
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