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diff --git a/src/Core/performance_CPU/TNV_core.c.v4.stdver b/src/Core/performance_CPU/TNV_core.c.v4.stdver
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+/*
+ * This work is part of the Core Imaging Library developed by
+ * Visual Analytics and Imaging System Group of the Science Technology
+ * Facilities Council, STFC
+ *
+ * Copyright 2017 Daniil Kazantsev
+ * Copyright 2017 Srikanth Nagella, Edoardo Pasca
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "TNV_core.h"
+
+
+inline void coefF(float *t, float M1, float M2, float M3, float sigma, int p, int q, int r) {
+ int ii, num;
+ float divsigma = 1.0f / sigma;
+ float sum, shrinkfactor;
+ float T,D,det,eig1,eig2,sig1,sig2,V1, V2, V3, V4, v0,v1,v2, mu1,mu2,sig1_upd,sig2_upd;
+ float proj[2] = {0};
+
+ // Compute eigenvalues of M
+ T = M1 + M3;
+ D = M1 * M3 - M2 * M2;
+ det = sqrt(MAX((T * T / 4.0f) - D, 0.0f));
+ eig1 = MAX((T / 2.0f) + det, 0.0f);
+ eig2 = MAX((T / 2.0f) - det, 0.0f);
+ sig1 = sqrt(eig1);
+ sig2 = sqrt(eig2);
+
+ // Compute normalized eigenvectors
+ V1 = V2 = V3 = V4 = 0.0f;
+
+ if(M2 != 0.0f)
+ {
+ v0 = M2;
+ v1 = eig1 - M3;
+ v2 = eig2 - M3;
+
+ mu1 = sqrtf(v0 * v0 + v1 * v1);
+ mu2 = sqrtf(v0 * v0 + v2 * v2);
+
+ if(mu1 > fTiny)
+ {
+ V1 = v1 / mu1;
+ V3 = v0 / mu1;
+ }
+
+ if(mu2 > fTiny)
+ {
+ V2 = v2 / mu2;
+ V4 = v0 / mu2;
+ }
+
+ } else
+ {
+ if(M1 > M3)
+ {
+ V1 = V4 = 1.0f;
+ V2 = V3 = 0.0f;
+
+ } else
+ {
+ V1 = V4 = 0.0f;
+ V2 = V3 = 1.0f;
+ }
+ }
+
+ // Compute prox_p of the diagonal entries
+ sig1_upd = sig2_upd = 0.0f;
+
+ if(p == 1)
+ {
+ sig1_upd = MAX(sig1 - divsigma, 0.0f);
+ sig2_upd = MAX(sig2 - divsigma, 0.0f);
+
+ } else if(p == INFNORM)
+ {
+ proj[0] = sigma * fabs(sig1);
+ proj[1] = sigma * fabs(sig2);
+
+ /*l1 projection part */
+ sum = fLarge;
+ num = 0l;
+ shrinkfactor = 0.0f;
+ while(sum > 1.0f)
+ {
+ sum = 0.0f;
+ num = 0;
+
+ for(ii = 0; ii < 2; ii++)
+ {
+ proj[ii] = MAX(proj[ii] - shrinkfactor, 0.0f);
+
+ sum += fabs(proj[ii]);
+ if(proj[ii]!= 0.0f)
+ num++;
+ }
+
+ if(num > 0)
+ shrinkfactor = (sum - 1.0f) / num;
+ else
+ break;
+ }
+ /*l1 proj ends*/
+
+ sig1_upd = sig1 - divsigma * proj[0];
+ sig2_upd = sig2 - divsigma * proj[1];
+ }
+
+ // Compute the diagonal entries of $\widehat{\Sigma}\Sigma^{\dagger}_0$
+ if(sig1 > fTiny)
+ sig1_upd /= sig1;
+
+ if(sig2 > fTiny)
+ sig2_upd /= sig2;
+
+ // Compute solution
+ t[0] = sig1_upd * V1 * V1 + sig2_upd * V2 * V2;
+ t[1] = sig1_upd * V1 * V3 + sig2_upd * V2 * V4;
+ t[2] = sig1_upd * V3 * V3 + sig2_upd * V4 * V4;
+}
+
+
+/*
+ * C-OMP implementation of Total Nuclear Variation regularisation model (2D + channels) [1]
+ * The code is modified from the implementation by Joan Duran <joan.duran@uib.es> see
+ * "denoisingPDHG_ipol.cpp" in Joans Collaborative Total Variation package
+ *
+ * Input Parameters:
+ * 1. Noisy volume of 2D + channel dimension, i.e. 3D volume
+ * 2. lambda - regularisation parameter
+ * 3. Number of iterations [OPTIONAL parameter]
+ * 4. eplsilon - tolerance constant [OPTIONAL parameter]
+ * 5. print information: 0 (off) or 1 (on) [OPTIONAL parameter]
+ *
+ * Output:
+ * 1. Filtered/regularized image (u)
+ *
+ * [1]. Duran, J., Moeller, M., Sbert, C. and Cremers, D., 2016. Collaborative total variation: a general framework for vectorial TV models. SIAM Journal on Imaging Sciences, 9(1), pp.116-151.
+ */
+
+float TNV_CPU_main(float *InputT, float *uT, float lambda, int maxIter, float tol, int dimX, int dimY, int dimZ)
+{
+ long i, j, k, p, q, r, DimTotal;
+ float taulambda;
+ float *u_upd, *qx, *qy, *qx_upd, *qy_upd, *gradx, *grady, *gradx_upd, *grady_upd, *div, *div_upd;
+
+ p = 1l;
+ q = 1l;
+ r = 0l;
+
+ lambda = 1.0f/(2.0f*lambda);
+ DimTotal = (long)(dimX*dimY*dimZ);
+ /* PDHG algorithm parameters*/
+ float tau = 0.5f;
+ float sigma = 0.5f;
+ float theta = 1.0f;
+
+ // Auxiliar vectors
+ u_upd = calloc(DimTotal, sizeof(float));
+ qx = calloc(DimTotal, sizeof(float));
+ qy = calloc(DimTotal, sizeof(float));
+ qx_upd = calloc(DimTotal, sizeof(float));
+ qy_upd = calloc(DimTotal, sizeof(float));
+ gradx = calloc(DimTotal, sizeof(float));
+ grady = calloc(DimTotal, sizeof(float));
+ gradx_upd = calloc(DimTotal, sizeof(float));
+ grady_upd = calloc(DimTotal, sizeof(float));
+ div = calloc(DimTotal, sizeof(float));
+ div_upd = calloc(DimTotal, sizeof(float));
+
+
+ float *Input = calloc(DimTotal, sizeof(float));
+ float *u = calloc(DimTotal, sizeof(float));
+ for(k=0; k<dimZ; k++) {
+ for(j=0; j<dimY; j++) {
+ for(i=0; i<dimX; i++) {
+ Input[j * dimX * dimZ + i * dimZ + k] = InputT[k * dimX * dimY + j * dimX + i];
+ u[j * dimX * dimZ + i * dimZ + k] = uT[k * dimX * dimY + j * dimX + i];
+ }
+ }
+ }
+
+
+ // Backtracking parameters
+ float s = 1.0f;
+ float gamma = 0.75f;
+ float beta = 0.95f;
+ float alpha0 = 0.2f;
+ float alpha = alpha0;
+ float delta = 1.5f;
+ float eta = 0.95f;
+
+ // PDHG algorithm parameters
+ taulambda = tau * lambda;
+ float divtau = 1.0f / tau;
+ float divsigma = 1.0f / sigma;
+ float theta1 = 1.0f + theta;
+
+ /*allocate memory for taulambda */
+ //taulambda = (float*) calloc(dimZ, sizeof(float));
+ //for(k=0; k < dimZ; k++) {taulambda[k] = tau*lambda[k];}
+
+ // Apply Primal-Dual Hybrid Gradient scheme
+ int iter = 0;
+ float residual = fLarge;
+
+ for(iter = 0; iter < maxIter; iter++) {
+ // Argument of proximal mapping of fidelity term
+ // Proximal solution of fidelity term
+ // proxG(u_upd, u, div, Input, tau, taulambda, (long)(dimX), (long)(dimY), (long)(dimZ));
+ float constant = 1.0f + taulambda;
+ #pragma omp parallel for shared(Input, u, u_upd) private(k)
+ for(k=0; k<dimZ*dimX*dimY; k++) {
+ float v = u[k] + tau * div[k];
+ u_upd[k] = (v + taulambda * Input[k])/constant;
+ }
+
+ memset(div_upd, 0, dimX*dimY*dimZ*sizeof(float));
+ // This changes results, I guess access to div_upd is violated
+// #pragma omp parallel for shared (gradx_upd,grady_upd,gradx,grady,qx,qy,qx_upd,qy_upd) private(i,j,k)
+ for(j=0; j<dimY; j++) {
+ for(i=0; i<dimX; i++) {
+ float t[3];
+ float M1 = 0.0f, M2 = 0.0f, M3 = 0.0f;
+ int l = (j * dimX + i) * dimZ;
+
+ for(k = 0; k < dimZ; k++) {
+ if(i != dimX-1)
+ gradx_upd[l + k] = u_upd[l + k + dimZ] - u_upd[l + k];
+ else
+ gradx_upd[l + k] = 0.0f;
+
+ if(j != dimY-1)
+ grady_upd[l + k] = u_upd[l + k + dimX * dimZ] - u_upd[l + k];
+ else
+ grady_upd[l + k] = 0.0f;
+
+ float ubarx = theta1 * gradx_upd[l + k] - theta * gradx[l + k];
+ float ubary = theta1 * grady_upd[l + k] - theta * grady[l + k];
+ float vx = ubarx + divsigma * qx[l + k];
+ float vy = ubary + divsigma * qy[l + k];
+
+ M1 += (vx * vx); M2 += (vx * vy); M3 += (vy * vy);
+ }
+
+ coefF(t, M1, M2, M3, sigma, p, q, r);
+
+ for(k = 0; k < dimZ; k++) {
+ float ubarx = theta1 * gradx_upd[l + k] - theta * gradx[l + k];
+ float ubary = theta1 * grady_upd[l + k] - theta * grady[l + k];
+ float vx = ubarx + divsigma * qx[l + k];
+ float vy = ubary + divsigma * qy[l + k];
+
+ float gx_upd = vx * t[0] + vy * t[1];
+ float gy_upd = vx * t[1] + vy * t[2];
+
+ qx_upd[l + k] = qx[l + k] + sigma * (ubarx - gx_upd);
+ qy_upd[l + k] = qy[l + k] + sigma * (ubary - gy_upd);
+
+ if(i != dimX-1) {
+ div_upd[l + k] += qx_upd[l + k];
+ div_upd[l + k + dimZ] -= qx_upd[l + k];
+ }
+
+ if(j != dimY-1) {
+ div_upd[l + k] += qy_upd[l + k];
+ div_upd[l + k + dimX * dimZ] -= qy_upd[l + k];
+ }
+ }
+ }
+ }
+
+// Compute primal residual, dual residual, and backtracking condition
+ float resprimal = 0.0f;
+ float resdual = 0.0f;
+ float product = 0.0f;
+ float unorm = 0.0f;
+ float qnorm = 0.0f;
+
+ // If this loop is inner, the result slightly changed due to different summation order
+ for(int l=0; l<dimZ; l++)
+ for(j=0; j<dimY; j++)
+ for(i=0; i<dimX; i++)
+ {
+// for(k=0; k<dimX*dimY*dimZ; k++) {
+ int k = j * dimX * dimZ + i * dimZ + l;
+
+ float udiff = u[k] - u_upd[k];
+ float qxdiff = qx[k] - qx_upd[k];
+ float qydiff = qy[k] - qy_upd[k];
+ float divdiff = div[k] - div_upd[k];
+ float gradxdiff = gradx[k] - gradx_upd[k];
+ float gradydiff = grady[k] - grady_upd[k];
+
+ resprimal += fabs(divtau*udiff + divdiff);
+ resdual += fabs(divsigma*qxdiff - gradxdiff);
+ resdual += fabs(divsigma*qydiff - gradydiff);
+
+ unorm += (udiff * udiff);
+ qnorm += (qxdiff * qxdiff + qydiff * qydiff);
+ product += (gradxdiff * qxdiff + gradydiff * qydiff);
+ }
+
+ float b = (2.0f * tau * sigma * product) / (gamma * sigma * unorm +
+ gamma * tau * qnorm);
+
+// printf("resprimal: %f, resdual: %f, b: %f\n", resprimal, resdual, b);
+ printf("resprimal: %f, resdual: %f, b: %f (product: %f, unorm: %f, qnorm: %f)\n", resprimal, resdual, b, product, unorm, qnorm);
+
+// printf("b: %f\n", b);
+
+// Adapt step-size parameters
+ float dual_dot_delta = resdual * s * delta;
+ float dual_div_delta = (resdual * s) / delta;
+
+ if(b > 1)
+ {
+ // Decrease step-sizes to fit balancing principle
+ tau = (beta * tau) / b;
+ sigma = (beta * sigma) / b;
+ alpha = alpha0;
+
+ copyIm(u, u_upd, (long)(dimX), (long)(dimY), (long)(dimZ));
+ copyIm(qx, qx_upd, (long)(dimX), (long)(dimY), (long)(dimZ));
+ copyIm(qy, qy_upd, (long)(dimX), (long)(dimY), (long)(dimZ));
+ copyIm(gradx, gradx_upd, (long)(dimX), (long)(dimY), (long)(dimZ));
+ copyIm(grady, grady_upd, (long)(dimX), (long)(dimY), (long)(dimZ));
+ copyIm(div, div_upd, (long)(dimX), (long)(dimY), (long)(dimZ));
+
+ } else if(resprimal > dual_dot_delta)
+ {
+ // Increase primal step-size and decrease dual step-size
+ tau = tau / (1.0f - alpha);
+ sigma = sigma * (1.0f - alpha);
+ alpha = alpha * eta;
+
+ } else if(resprimal < dual_div_delta)
+ {
+ // Decrease primal step-size and increase dual step-size
+ tau = tau * (1.0f - alpha);
+ sigma = sigma / (1.0f - alpha);
+ alpha = alpha * eta;
+ }
+
+// Update variables
+ taulambda = tau * lambda;
+//for(k=0; k < dimZ; k++) taulambda[k] = tau*lambda[k];
+
+ divsigma = 1.0f / sigma;
+ divtau = 1.0f / tau;
+
+ copyIm(u_upd, u, (long)(dimX), (long)(dimY), (long)(dimZ));
+ copyIm(qx_upd, qx, (long)(dimX), (long)(dimY), (long)(dimZ));
+ copyIm(qy_upd, qy, (long)(dimX), (long)(dimY), (long)(dimZ));
+ copyIm(gradx_upd, gradx, (long)(dimX), (long)(dimY), (long)(dimZ));
+ copyIm(grady_upd, grady, (long)(dimX), (long)(dimY), (long)(dimZ));
+ copyIm(div_upd, div, (long)(dimX), (long)(dimY), (long)(dimZ));
+
+// Compute residual at current iteration
+ residual = (resprimal + resdual) / ((float) (dimX*dimY*dimZ));
+
+// printf("%f \n", residual);
+ if (residual < tol) {
+ printf("Iterations stopped at %i with the residual %f \n", iter, residual);
+ break;
+ }
+
+ }
+ printf("Iterations stopped at %i with the residual %f \n", iter, residual);
+
+ free (u_upd);
+ free(qx);
+ free(qy);
+ free(qx_upd);
+ free(qy_upd);
+ free(gradx);
+ free(grady);
+ free(gradx_upd);
+ free(grady_upd);
+ free(div);
+ free(div_upd);
+ printf("Return: %f\n", *u);
+
+ for(k=0; k<dimZ; k++) {
+ for(j=0; j<dimY; j++) {
+ for(i=0; i<dimX; i++) {
+ uT[k * dimX * dimY + j * dimX + i] = u[j * dimX * dimZ + i * dimZ + k];
+ }
+ }
+ }
+
+
+
+
+ return *u;
+}
+
+float proxG(float *u_upd, float *v, float *f, float taulambda, long dimX, long dimY, long dimZ)
+{
+ float constant;
+ long k;
+ constant = 1.0f + taulambda;
+ #pragma omp parallel for shared(v, f, u_upd) private(k)
+ for(k=0; k<dimZ*dimX*dimY; k++) {
+ u_upd[k] = (v[k] + taulambda * f[k])/constant;
+ //u_upd[(dimX*dimY)*k + l] = (v[(dimX*dimY)*k + l] + taulambda * f[(dimX*dimY)*k + l])/constant;
+ }
+ return *u_upd;
+}
+
+float gradient(float *u_upd, float *gradx_upd, float *grady_upd, long dimX, long dimY, long dimZ)
+{
+ long i, j, k, l;
+ // Compute discrete gradient using forward differences
+ #pragma omp parallel for shared(gradx_upd,grady_upd,u_upd) private(i, j, k, l)
+ for(k = 0; k < dimZ; k++) {
+ for(j = 0; j < dimY; j++) {
+ l = j * dimX;
+ for(i = 0; i < dimX; i++) {
+ // Derivatives in the x-direction
+ if(i != dimX-1)
+ gradx_upd[(dimX*dimY)*k + i+l] = u_upd[(dimX*dimY)*k + i+1+l] - u_upd[(dimX*dimY)*k + i+l];
+ else
+ gradx_upd[(dimX*dimY)*k + i+l] = 0.0f;
+
+ // Derivatives in the y-direction
+ if(j != dimY-1)
+ //grady_upd[(dimX*dimY)*k + i+l] = u_upd[(dimX*dimY)*k + i+dimY+l] -u_upd[(dimX*dimY)*k + i+l];
+ grady_upd[(dimX*dimY)*k + i+l] = u_upd[(dimX*dimY)*k + i+(j+1)*dimX] -u_upd[(dimX*dimY)*k + i+l];
+ else
+ grady_upd[(dimX*dimY)*k + i+l] = 0.0f;
+ }
+ }
+ }
+ return 1;
+}
+
+float proxF(float *gx, float *gy, float *vx, float *vy, float sigma, int p, int q, int r, long dimX, long dimY, long dimZ)
+{
+ // (S^p, \ell^1) norm decouples at each pixel
+// Spl1(gx, gy, vx, vy, sigma, p, num_channels, dim);
+ float divsigma = 1.0f / sigma;
+
+ // $\ell^{1,1,1}$-TV regularization
+// int i,j,k;
+// #pragma omp parallel for shared (gx,gy,vx,vy) private(i,j,k)
+// for(k = 0; k < dimZ; k++) {
+// for(i=0; i<dimX; i++) {
+// for(j=0; j<dimY; j++) {
+// gx[(dimX*dimY)*k + (i)*dimY + (j)] = SIGN(vx[(dimX*dimY)*k + (i)*dimY + (j)]) * MAX(fabs(vx[(dimX*dimY)*k + (i)*dimY + (j)]) - divsigma, 0.0f);
+// gy[(dimX*dimY)*k + (i)*dimY + (j)] = SIGN(vy[(dimX*dimY)*k + (i)*dimY + (j)]) * MAX(fabs(vy[(dimX*dimY)*k + (i)*dimY + (j)]) - divsigma, 0.0f);
+// }}}
+
+ // Auxiliar vector
+ float *proj, sum, shrinkfactor ;
+ float M1,M2,M3,valuex,valuey,T,D,det,eig1,eig2,sig1,sig2,V1, V2, V3, V4, v0,v1,v2, mu1,mu2,sig1_upd,sig2_upd,t1,t2,t3;
+ long i,j,k, ii, num;
+ #pragma omp parallel for shared (gx,gy,vx,vy,p) private(i,ii,j,k,proj,num, sum, shrinkfactor, M1,M2,M3,valuex,valuey,T,D,det,eig1,eig2,sig1,sig2,V1, V2, V3, V4,v0,v1,v2,mu1,mu2,sig1_upd,sig2_upd,t1,t2,t3)
+ for(i=0; i<dimX; i++) {
+ for(j=0; j<dimY; j++) {
+
+ proj = (float*) calloc (2,sizeof(float));
+ // Compute matrix $M\in\R^{2\times 2}$
+ M1 = 0.0f;
+ M2 = 0.0f;
+ M3 = 0.0f;
+
+ for(k = 0; k < dimZ; k++)
+ {
+ valuex = vx[(dimX*dimY)*k + (j)*dimX + (i)];
+ valuey = vy[(dimX*dimY)*k + (j)*dimX + (i)];
+
+ M1 += (valuex * valuex);
+ M2 += (valuex * valuey);
+ M3 += (valuey * valuey);
+ }
+
+ // Compute eigenvalues of M
+ T = M1 + M3;
+ D = M1 * M3 - M2 * M2;
+ det = sqrt(MAX((T * T / 4.0f) - D, 0.0f));
+ eig1 = MAX((T / 2.0f) + det, 0.0f);
+ eig2 = MAX((T / 2.0f) - det, 0.0f);
+ sig1 = sqrt(eig1);
+ sig2 = sqrt(eig2);
+
+ // Compute normalized eigenvectors
+ V1 = V2 = V3 = V4 = 0.0f;
+
+ if(M2 != 0.0f)
+ {
+ v0 = M2;
+ v1 = eig1 - M3;
+ v2 = eig2 - M3;
+
+ mu1 = sqrtf(v0 * v0 + v1 * v1);
+ mu2 = sqrtf(v0 * v0 + v2 * v2);
+
+ if(mu1 > fTiny)
+ {
+ V1 = v1 / mu1;
+ V3 = v0 / mu1;
+ }
+
+ if(mu2 > fTiny)
+ {
+ V2 = v2 / mu2;
+ V4 = v0 / mu2;
+ }
+
+ } else
+ {
+ if(M1 > M3)
+ {
+ V1 = V4 = 1.0f;
+ V2 = V3 = 0.0f;
+
+ } else
+ {
+ V1 = V4 = 0.0f;
+ V2 = V3 = 1.0f;
+ }
+ }
+
+ // Compute prox_p of the diagonal entries
+ sig1_upd = sig2_upd = 0.0f;
+
+ if(p == 1)
+ {
+ sig1_upd = MAX(sig1 - divsigma, 0.0f);
+ sig2_upd = MAX(sig2 - divsigma, 0.0f);
+
+ } else if(p == INFNORM)
+ {
+ proj[0] = sigma * fabs(sig1);
+ proj[1] = sigma * fabs(sig2);
+
+ /*l1 projection part */
+ sum = fLarge;
+ num = 0l;
+ shrinkfactor = 0.0f;
+ while(sum > 1.0f)
+ {
+ sum = 0.0f;
+ num = 0;
+
+ for(ii = 0; ii < 2; ii++)
+ {
+ proj[ii] = MAX(proj[ii] - shrinkfactor, 0.0f);
+
+ sum += fabs(proj[ii]);
+ if(proj[ii]!= 0.0f)
+ num++;
+ }
+
+ if(num > 0)
+ shrinkfactor = (sum - 1.0f) / num;
+ else
+ break;
+ }
+ /*l1 proj ends*/
+
+ sig1_upd = sig1 - divsigma * proj[0];
+ sig2_upd = sig2 - divsigma * proj[1];
+ }
+
+ // Compute the diagonal entries of $\widehat{\Sigma}\Sigma^{\dagger}_0$
+ if(sig1 > fTiny)
+ sig1_upd /= sig1;
+
+ if(sig2 > fTiny)
+ sig2_upd /= sig2;
+
+ // Compute solution
+ t1 = sig1_upd * V1 * V1 + sig2_upd * V2 * V2;
+ t2 = sig1_upd * V1 * V3 + sig2_upd * V2 * V4;
+ t3 = sig1_upd * V3 * V3 + sig2_upd * V4 * V4;
+
+ for(k = 0; k < dimZ; k++)
+ {
+ gx[(dimX*dimY)*k + j*dimX + i] = vx[(dimX*dimY)*k + j*dimX + i] * t1 + vy[(dimX*dimY)*k + j*dimX + i] * t2;
+ gy[(dimX*dimY)*k + j*dimX + i] = vx[(dimX*dimY)*k + j*dimX + i] * t2 + vy[(dimX*dimY)*k + j*dimX + i] * t3;
+ }
+
+ // Delete allocated memory
+ free(proj);
+ }
+ }
+
+ return 1;
+}
+
+float divergence(float *qx_upd, float *qy_upd, float *div_upd, long dimX, long dimY, long dimZ)
+{
+ long i, j, k, l;
+ #pragma omp parallel for shared(qx_upd,qy_upd,div_upd) private(i, j, k, l)
+ for(k = 0; k < dimZ; k++) {
+ for(j = 0; j < dimY; j++) {
+ l = j * dimX;
+ for(i = 0; i < dimX; i++) {
+ if(i != dimX-1)
+ {
+ // ux[k][i+l] = u[k][i+1+l] - u[k][i+l]
+ div_upd[(dimX*dimY)*k + i+1+l] -= qx_upd[(dimX*dimY)*k + i+l];
+ div_upd[(dimX*dimY)*k + i+l] += qx_upd[(dimX*dimY)*k + i+l];
+ }
+
+ if(j != dimY-1)
+ {
+ // uy[k][i+l] = u[k][i+width+l] - u[k][i+l]
+ //div_upd[(dimX*dimY)*k + i+dimY+l] -= qy_upd[(dimX*dimY)*k + i+l];
+ div_upd[(dimX*dimY)*k + i+(j+1)*dimX] -= qy_upd[(dimX*dimY)*k + i+l];
+ div_upd[(dimX*dimY)*k + i+l] += qy_upd[(dimX*dimY)*k + i+l];
+ }
+ }
+ }
+ }
+ return *div_upd;
+}