19 lines
470 B
C
19 lines
470 B
C
#include "cs.h"
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/* solve Ux=b where x and b are dense. x=b on input, solution on output. */
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int cs_usolve (const cs *U, double *x)
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{
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int p, j, n, *Up, *Ui ;
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double *Ux ;
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if (!CS_CSC (U) || !x) return (0) ; /* check inputs */
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n = U->n ; Up = U->p ; Ui = U->i ; Ux = U->x ;
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for (j = n-1 ; j >= 0 ; j--)
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{
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x [j] /= Ux [Up [j+1]-1] ;
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for (p = Up [j] ; p < Up [j+1]-1 ; p++)
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{
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x [Ui [p]] -= Ux [p] * x [j] ;
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}
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}
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return (1) ;
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}
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