/* Report from Ansely Manke: I've attached a file with a short c program that demonstrates what I'm seeing. I don't know that we'd call this a constraint, so that was a misleading description. The thing I'm mimicking is a sequence where I read the 2-D coordinate variables, make some decisions about the size of a subset region, and then define index ranges and strides for reading other variables. Reading the full variable happens correctly, but the read with strides winds up messing up the data. Here it shows up returning some valid data and some zero's, but in other sequences of events it seems to be actually mis-ordered. I notice that the results are correct if the initial read of the variable uses counts that are size-1. So that might be a clue. And the read is correct if I either close and reopen the dataset after reading the original full variable, or if I don't do that step of first reading the whole grid. It's also fine with NetCDF 4.2.1.1. -Ansley Problem was two-fold: 1. struct Getvara has the dsttype field as OC_Type rather than nc_type 2. the dap odometer code dapnew_segment was incorrectly handling strides > 1: specifically, the stop position was incorrect. */ /* vars_whoi_test */ /* acm 4/2013 */ /* ansley.b.manke@noaa.gov */ /* test nc_get_vars_float with calls similar to Ferret calls */ /*linked with: cc vars_whoi_test.c -g -o vars_whoi_test_4211 /usr/local/netcdf_4211/lib/libnetcdf.a /usr/local/hdf5_189/lib/libhdf5_hl.a /usr/local/hdf5_189/lib/libhdf5.a /usr/local/lib/libz.a -L/usr/lib64 -lc -lm -lcurl cc vars_whoi_test.c -g -o vars_whoi_test /home/users/ansley/local/x86_nc43/lib/libnetcdf.a /usr/local/hdf5_189/lib/libhdf5_hl.a /usr/local/hdf5_189/lib/libhdf5.a /usr/local/lib/libz.a -L/usr/lib64 -lc -lm -lcurl Closing and reopening the dataset between the two reads fixes the incorrect data return Setting the count to one less in the full data read also fixes the incorrect data return */ #include #include #include #include "netcdf.h" #include "ncdispatch.h" #include "nctestserver.h" #define VERBOSE 1 /* 2014-07-01: (DMH) Changed the URL to use one from remotetest server. to remove dependence on an external server. */ /* static char* URL="http://geoport.whoi.edu/thredds/dodsC/coawst_4/use/fmrc/coawst_4_use_best.ncd"; Float64 lon_rho[eta_rho = 336][xi_rho = 896]; Float64 lat_rho[eta_rho = 336][xi_rho = 896]; */ #define URL "%s/dodsC/testdods/rtofs.nc" #define VAR1 "Latitude" #define VAR2 "Longitude" #define XSIZE 850 #define YSIZE 712 static char url[1024]; int main() { int ncid; int varid; int i; int ncstatus; size_t start[5], count[5]; ptrdiff_t stride[5]; int pass = 1; int nelems = XSIZE*YSIZE; int idim, ndim; float *dat = (float*)malloc(sizeof(float)*nelems); float sdat[10]; char* svc; /* Find Test Server */ svc = nc_findtestserver("thredds",0,REMOTETESTSERVERS); if(svc == NULL) { fprintf(stderr,"Cannot locate test server\n"); exit(0); } snprintf(url,sizeof(url),URL,svc); for (idim=0; idim<5; idim++) { start[idim] = 0; count[idim] = 1; stride[idim] = 1; } ndim=2; printf(" \n"); printf("********************\n"); printf("open URL %s\n",url); printf(" \n"); ncstatus = nc_open(url, NC_NOWRITE, &ncid); if(ncstatus != NC_NOERR) { fprintf(stderr,"Could not open: %s; server may be down; test ignored\n",url); exit(0); } ncstatus = nc_inq_varid(ncid, VAR1, &varid); ndim=2; #ifdef VERBOSE printf(" \n"); printf("********************\n"); printf("Read %s data w/o strides\n",VAR1); printf(" \n"); #endif start[0] = 0; start[1] = 0; start[2] = 0; start[3] = 0; count[0] = XSIZE; count[1] = YSIZE; stride[0] = 1; stride[1] = 1; #ifdef VERBOSE for (idim=0; idim 51.0) { printf("Out of range: %s[%d] = %f\n",VAR1, i,sdat[i]); pass = 0; } } #ifdef VERBOSE printf(" \n"); printf("********************\n"); printf("Print values read. They should all be 50.xxxx \n"); printf(" \n"); for (i=0; i<10; i++) printf("%s[%d] = %f\n",VAR1,i,sdat[i]); #endif ncstatus = nc_close (ncid); if(!pass) { printf("*** FAIL: %s value out of range.\n",VAR1); exit(1); } printf("*** PASS\n"); free(dat); exit(0); }