69 lines
2.4 KiB
C
69 lines
2.4 KiB
C
/*************************************************************************/
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/* */
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/* Copyright (c) 1994 Stanford University */
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/* */
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/* All rights reserved. */
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/* */
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/* Permission is given to use, copy, and modify this software for any */
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/* non-commercial purpose as long as this copyright notice is not */
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/* removed. All other uses, including redistribution in whole or in */
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/* part, are forbidden without prior written permission. */
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/* */
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/* This software is provided with absolutely no warranty and no */
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/* support. */
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/* */
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/*************************************************************************/
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/* **************************************************************
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end of subroutine jacobcalc
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**************************************************************
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performs the laplacian calculation for a subblock. */
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#include <stdio.h>
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#include <math.h>
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#include <time.h>
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#include "decs.h"
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void laplacalc(double x[IMAX][JMAX], double z[IMAX][JMAX], long firstrow, long lastrow, long firstcol, long lastcol, long numrows, long numcols)
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{
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long iindex;
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long indexp1;
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long indexm1;
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long ip1;
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long im1;
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long i;
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long j;
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for (iindex=firstcol;iindex<=lastcol;iindex++) {
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indexp1 = iindex+1;
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indexm1 = iindex-1;
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for (i=firstrow;i<=lastrow;i++) {
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ip1 = i+1;
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im1 = i-1;
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z[i][iindex] = factlap*(x[ip1][iindex]+x[im1][iindex]+x[i][indexp1]+
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x[i][indexm1]-4.*x[i][iindex]);
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}
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}
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if (firstrow == 1) {
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for (j=firstcol;j<=lastcol;j++) {
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z[0][j] = 0.0;
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}
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}
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if ((firstrow+numrows) == im-1) {
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for (j=firstcol;j<=lastcol;j++) {
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z[im-1][j] = 0.0;
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}
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}
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if (firstcol == 1) {
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for (j=firstrow;j<=lastrow;j++) {
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z[j][0] = 0.0;
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}
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}
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if ((firstcol+numcols) == jm-1) {
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for (j=firstrow;j<=lastrow;j++) {
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z[j][jm-1] = 0.0;
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}
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}
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}
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