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How do I read/write files in parallel using UDF? |
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#1 |
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Join Date: Nov 2022
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Hey all, I'm trying to create a udf that reads a file containing x,y,z coordinates and then returning the value of the cell nearest to it. I managed to create the code, but I have trouble parallelizing it. At first, I had trouble because ansys repeats my udf 4 times (which is equal to the number of solver processes I input), so I decided to just use my udf on compute node zero by using if(I_AM_NODE_ZERO_P). However, I began to realize that this will fail because the other compute nodes will not be processed, and thus the I will not get the cell values at those compute nodes. My question now is, how do I parallelize reading/writing csv files using UDF? I consulted the ansys documentation on parallelizing udf, but I do not know how to start. Here is my code:
Code:
#include <udf.h> #include <cxndsearch.h> #include <stdio.h> #include <stdlib.h> #include <string.h> static ND_Search *domain_table = NULL; DEFINE_ON_DEMAND(find_cells) { #if !RP_HOST if(I_AM_NODE_ZERO_P){ cell_t c; Thread *t; CX_Cell_Id *cx_cell; real cCentroid; real cVolume; real P[3]; real P_Cell[3]; FILE *fp; char line[1024]; int rayID, side, prevID, nextID, surfID; double x,y,z; fp = fopen("rays_csv_new.csv","r"); if(fp == NULL){ printf("Trouble reading file\nAborting.."); fclose(fp); abort(); } domain_table = CX_Start_ND_Point_Search(domain_table,TRUE,-1); Message("Starting Cell Search..."); while(fgets(line,1024,fp)){ sscanf(line,"%d,%lg,%lg,%lg,%d,%d,%d,%d",&rayID,&x,&y,&z,&side,&prevID,&nextID,&surfID); P[0] = x; P[1] = y; P[2] = z; cx_cell = CX_Find_Cell_With_Point(domain_table,P,0.0); if(cx_cell){ c = RP_CELL(cx_cell); t = RP_THREAD(cx_cell); cCentroid = C_CENTROID(P_Cell,c,t); cVolume = C_VOLUME(c,t); Message("%g \t %g \t %g \t %g\n",P[0],P[1],P[2],cVolume); }else{ Message("Could not find cell at [%g,%g,%g]\n",P[0],P[1],P[2]); } } domain_table = CX_End_ND_Point_Search(domain_table); fclose(fp); } #endif } Code:
x y z 0.227898,1.0,-0.448053 4,-0.106937,1.0,0.379007 7,-0.350153,1.0,0.031367 9,0.293532,1.0,0.357582 11,-0.403077,1.0,-0.409584 13,0.476352,1.0,-0.0787738 15,-0.400827,1.0,-0.0563139 18,0.189004,1.0,0.217153 Code:
Could not find cell at [0.227898,1,-0.448053] Could not find cell at [-0.106937,1,0.379007] Could not find cell at [-0.350153,1,0.0313674] 0.293532 1 0.357582 1.82506e-08 Could not find cell at [-0.403077,1,-0.409584] Could not find cell at [0.476352,1,-0.0787738] Could not find cell at [-0.400827,1,-0.0563139] 0.189004 1 0.217153 1.95857e-08 |
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#2 |
Senior Member
Alexander
Join Date: Apr 2013
Posts: 2,363
Rep Power: 34 ![]() ![]() |
try this code,
modify FL variable which represents the number of lines into your table file Code:
#include <udf.h> #include <cxndsearch.h> #include <stdio.h> #include <stdlib.h> #include <string.h> #define FL 100 /*file length*/ static ND_Search *domain_table = NULL; int rayID[FL], side[FL], prevID[FL], nextID[FL], surfID[FL]; real x[FL],y[FL],z[FL]; void my_read_from_table(char *file) { FILE *fp; char line[1024]; int i=0; fp = fopen(file,"r"); if(fp == NULL){ printf("Trouble reading file\nAborting.."); fclose(fp); abort(); } while(fgets(line,1024,fp)){ sscanf(line,"%d,%lf,%lf,%lf,%d,%d,%d,%d",&rayID[i],&x[i],&y[i],&z[i],&side[i],&prevID[i],&nextID[i],&surfID[i]); i++; } fclose(fp); Message("DEBUG: last line from table:\n %d,%f,%f,%f,%d,%d,%d,%d \n",rayID[FL],x[FL],y[FL],z[FL],side[FL],prevID[FL],nextID[FL],surfID[FL]); } DEFINE_ON_DEMAND(find_cells) { cell_t c; Thread *t; CX_Cell_Id *cx_cell; real cCentroid; real cVolume; real P[3]; real P_Cell[3]; int i; #if !RP_NODE my_read_from_table("rays_csv_new.csv"); #endif host_to_node_int(rayID,FL); host_to_node_int(side,FL); host_to_node_int(prevID,FL); host_to_node_int(nextID,FL); host_to_node_int(surfID,FL); host_to_node_int(x,FL); host_to_node_int(y,FL); host_to_node_int(z,FL); #if !RP_HOST domain_table = CX_Start_ND_Point_Search(domain_table,TRUE,-1); Message0("Starting Cell Search..."); for (i=0;i<FL;i++) { P[0] = x[i]; P[1] = y[i]; P[2] = z[i]; cx_cell = CX_Find_Cell_With_Point(domain_table,P,0.0); if(cx_cell){ c = RP_CELL(cx_cell); t = RP_THREAD(cx_cell); cCentroid = C_CENTROID(P_Cell,c,t); cVolume = C_VOLUME(c,t); Message0("%f \t %f \t %f \t %f\n",P[0],P[1],P[2],cVolume); }else{ Message0("Could not find cell at [%f,%f,%f]\n",P[0],P[1],P[2]); } } domain_table = CX_End_ND_Point_Search(domain_table); #endif }
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#3 | |
New Member
Join Date: Nov 2022
Posts: 10
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Quote:
Could not find cell at [0.000000,0.000000,0.000000] Could not find cell at [0.000000,0.000000,0.000000] Could not find cell at [0.000000,0.000000,0.000000] But I don't think this thread matters anymore since I've decided to just use a serial solver to do the udf. I was hoping you could help me with my other problem located here |
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parallel, udf |
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