fc6c4acd79
Makefiles modified to generate a Linux SICServer. Other files modified to get rid of irritating compiler warning messages.
77 lines
1.5 KiB
C
77 lines
1.5 KiB
C
/*
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*-----------------------------------------------------------------------------
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* file: matinv.c
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* desc: matrix inversion
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* by: ko shu pui, patrick
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* date: 24 nov 91 v0.1
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* revi: 14 may 92 v0.2
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* ref:
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* [1] Mary L.Boas, "Mathematical Methods in the Physical Sciene,"
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* John Wiley & Sons, 2nd Ed., 1983. Chap 3.
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*
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* [2] Kendall E.Atkinson, "An Introduction to Numberical Analysis,"
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* John Wiley & Sons, 1978.
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*
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*-----------------------------------------------------------------------------
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*/
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#include <stdio.h>
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#include <math.h>
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#ifdef __TURBOC__
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#include <alloc.h>
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#else
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#include <malloc.h>
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#endif
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#include "matrix.h"
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/*
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*-----------------------------------------------------------------------------
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* funct: mat_inv
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* desct: find inverse of a matrix
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* given: a = square matrix a
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* retrn: square matrix Inverse(A)
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* NULL = fails, singular matrix, or malloc() fails
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*-----------------------------------------------------------------------------
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*/
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MATRIX mat_inv( a )
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MATRIX a;
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{
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MATRIX A, B, C, P;
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int i, j, n;
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double temp;
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n = MatCol(a);
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A = mat_copy(a);
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B = mat_creat( n, 1, UNDEFINED );
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C = mat_creat( n, n, UNDEFINED );
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P = mat_creat( n, 1, UNDEFINED );
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/*
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* - LU-decomposition -
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* also check for singular matrix
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*/
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if (mat_lu(A, P) == -1)
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{
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mat_free(A);
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mat_free(B);
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mat_free(C);
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mat_free(P);
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return (NULL);
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}
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for (i=0; i<n; i++)
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{
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mat_fill(B, ZERO_MATRIX);
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B[i][0] = 1.0;
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mat_backsubs1( A, B, C, P, i );
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}
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mat_free(A);
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mat_free(B);
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mat_free(P);
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return (C);
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}
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