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Matrix multiplication: Difference between revisions
→{{header|Prolog}}: Added PureBasic
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mmult(M1, M2, M3) :- transpose(M2,MT), maplist(mm_helper(MT), M1, M3).
mm_helper(M2, I1, M3) :- maplist(dot(I1), M2, M3).</lang>
=={{header|PureBasic}}==
Matrices represented as integer arrays with rows in the first dimension and columns in the second.
<lang PureBasic>Procedure multiplyMatrix(Array a(2), Array b(2), Array prd(2))
Protected ar = ArraySize(a()) ;#rows for matrix a
Protected ac = ArraySize(a(), 2) ;#cols for matrix a
Protected br = ArraySize(b()) ;#rows for matrix b
Protected bc = ArraySize(b(), 2) ;#cols for matrix b
If ac = br
Dim prd(ar, bc)
Protected i, j, k
For i = 0 To ar
For j = 0 To bc
For k = 0 To br ;ac
prd(i, j) = prd(i, j) + (a(i, k) * b(k, j))
Next
Next
Next
ProcedureReturn #True ;multiplication performed, product in prd()
Else
ProcedureReturn #False ;multiplication not performed, dimensions invalid
EndIf
EndProcedure</lang>
Additional code to demonstrate use.
<lang PureBasic>DataSection
Data.i 2,3 ;matrix a (#rows, #cols)
Data.i 1,2,3, 4,5,6 ;elements by row
Data.i 3,1 ;matrix b (#rows, #cols)
Data.i 1, 5, 9 ;elements by row
EndDataSection
Procedure displayMatrix(Array a(2), text.s)
Protected i, j
Protected columns = ArraySize(a(), 2), Rows = ArraySize(a(), 1)
PrintN(text + ": (" + Str(Rows + 1) + ", " + Str(columns + 1) + ")")
For i = 0 To Rows
For j = 0 To columns
Print(LSet(Str(a(i, j)), 4, " "))
Next
PrintN("")
Next
PrintN("")
EndProcedure
Procedure loadMatrix(Array a(2))
Protected Rows, columns, i, j
Read.i Rows
Read.i columns
Dim a(Rows - 1, columns - 1)
For i = 0 To Rows - 1
For j = 0 To columns - 1
Read.i a(i, j)
Next
Next
EndProcedure
Dim a(0,0)
Dim b(0,0)
Dim c(0,0)
If OpenConsole()
loadMatrix(a())
displayMatrix(a(), "matrix a")
loadMatrix(b())
displayMatrix(b(), "matrix b")
If multiplyMatrix(a(), b(), c())
displayMatrix(c(), "product of a * b")
Else
PrintN("product of a * b is undefined")
EndIf
Print(#CRLF$ + #CRLF$ + "Press ENTER to exit")
Input()
CloseConsole()
EndIf</lang>
Sample output:
<pre>matrix a: (2, 3)
1 2 3
4 5 6
matrix b: (3, 1)
1
5
9
product of a * b: (2, 1)
38
83</pre>
=={{header|Python}}==
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