A-M baby

Task/Factorial/Tcl/factorial-1.tcl

@@ -0,0 +1,6 @@
+proc ifact n {
+    for {set i $n; set sum 1} {$i >= 2} {incr i -1} {
+        set sum [expr {$sum * $i}]
+    }
+    return $sum
+}

Task/Factorial/Tcl/factorial-2.tcl

@@ -0,0 +1,3 @@
+proc rfact n {
+    expr {$n < 2 ? 1 : $n * [rfact [incr n -1]]}
+}

Task/Factorial/Tcl/factorial-3.tcl

@@ -0,0 +1 @@
+proc tcl::mathfunc::fact n {expr {$n < 2? 1: $n*fact($n-1)}}

Task/Factorial/Tcl/factorial-4.tcl

@@ -0,0 +1,17 @@
+proc ifact_caching n {
+    global fact_cache
+    if { ! [info exists fact_cache]} {
+        set fact_cache {1 1}
+    }
+    if {$n < [llength $fact_cache]} {
+        return [lindex $fact_cache $n]
+    }
+    set i [expr {[llength $fact_cache] - 1}]
+    set sum [lindex $fact_cache $i]
+    while {$i < $n} {
+        incr i
+        set sum [expr {$sum * $i}]
+        lappend fact_cache $sum
+    }
+    return $sum
+}

Task/Factorial/Tcl/factorial-5.tcl

@@ -0,0 +1,11 @@
+puts [ifact 30]
+puts [rfact 30]
+puts [ifact_caching 30]
+
+set n 400
+set iterations 10000
+puts "calculate $n factorial $iterations times"
+puts "ifact: [time {ifact $n} $iterations]"
+puts "rfact: [time {rfact $n} $iterations]"
+# for the caching proc, reset the cache between each iteration so as not to skew the results
+puts "ifact_caching: [time {ifact_caching $n; unset -nocomplain fact_cache} $iterations]"

Task/Factorial/Tcl/factorial-6.tcl

@@ -0,0 +1,5 @@
+package require math::special
+
+proc gfact n {
+    expr {round([::math::special::Gamma [expr {$n+1}]])}
+}