diff --git a/libdispatch/dvar.c b/libdispatch/dvar.c index da748474a..0f02d33cb 100644 --- a/libdispatch/dvar.c +++ b/libdispatch/dvar.c @@ -491,7 +491,17 @@ nc_def_var_deflate(int ncid, int varid, int shuffle, int deflate, int deflate_le to the data. Quantization is not applied to values equal to the value of the - _FillValue attribute, if any. + _FillValue attribute, if any. If the _FillValue attribute is not + set, then quantization is not applied to values matching the + default fill value. + + Quantization may be applied to scalar variables. + + When type conversion takes place during a write, the it occurs + before quantization is applied. For example, if nc_put_var_double() + is called on a variable of type NC_FLOAT, which has quantizze + turned on, then the data are first converted from dounle to float, + then quantization is applied to the float values. As with the deflate settings, quantize settings may only be modified before the first call to nc_enddef(). Once nc_enddef() is diff --git a/nc_test4/tst_quantize.c b/nc_test4/tst_quantize.c index 0c2181fdd..182c76bc9 100644 --- a/nc_test4/tst_quantize.c +++ b/nc_test4/tst_quantize.c @@ -402,6 +402,66 @@ main(int argc, char **argv) } } SUMMARIZE_ERR; + printf("**** testing quantization of one value with type conversion..."); + { + int ncid, dimid, varid1, varid2; + int quantize_mode_in, nsd_in; + float float_data[DIM_LEN_1] = {1.1111111}; + double double_data[DIM_LEN_1] = {1.111111111111}; + + /* Create a netcdf-4 file with two vars. */ + if (nc_create(FILE_NAME, NC_NETCDF4|NC_CLOBBER, &ncid)) ERR; + if (nc_def_dim(ncid, DIM_NAME_1, DIM_LEN_1, &dimid)) ERR; + if (nc_def_var(ncid, VAR_NAME_1, NC_FLOAT, NDIMS1, &dimid, &varid1)) ERR; + if (nc_def_var(ncid, VAR_NAME_2, NC_DOUBLE, NDIMS1, &dimid, &varid2)) ERR; + + /* Turn on quantize for both vars. */ + if (nc_def_var_quantize(ncid, varid1, NC_QUANTIZE_BITGROOM, NSD_3)) ERR; + if (nc_def_var_quantize(ncid, varid2, NC_QUANTIZE_BITGROOM, NSD_3)) ERR; + + /* Write some double data to float var. */ + if (nc_put_var_double(ncid, varid1, double_data)) ERR; + + /* Write some float data to double var. */ + if (nc_put_var_float(ncid, varid2, float_data)) ERR; + + /* Close the file. */ + if (nc_close(ncid)) ERR; + + { + float float_in; + double double_in; + union FU fin; + /* union FU fout; */ + union DU dfin; + /* union DU dfout; */ + + /* Open the file and check metadata. */ + if (nc_open(FILE_NAME, NC_WRITE, &ncid)) ERR; + if (nc_inq_var_quantize(ncid, 0, &quantize_mode_in, &nsd_in)) ERR; + if (quantize_mode_in != NC_QUANTIZE_BITGROOM || nsd_in != NSD_3) ERR; + if (nc_inq_var_quantize(ncid, 1, &quantize_mode_in, &nsd_in)) ERR; + if (quantize_mode_in != NC_QUANTIZE_BITGROOM || nsd_in != NSD_3) ERR; + + /* Check the data. */ + if (nc_get_var(ncid, varid1, &float_in)) ERR; + if (nc_get_var(ncid, varid2, &double_in)) ERR; + /* fout.f = float_data[0]; */ + fin.f = float_in; + /* dfout.d = double_data[0]; */ + dfin.d = double_in; + /* printf ("\nfloat_data: %10f : 0x%x float_data_in: %10f : 0x%x\n", */ + /* float_data[0], fout.u, float_data[0], fin.u); */ + /* if (fin.u != 0x3f8e3000) ERR; */ + /* printf ("\ndouble_data: %15g : 0x%16lx double_data_in: %15g : 0x%lx\n", */ + /* double_data[0], dfout.u, double_data[0], dfin.u); */ + /* if (dfin.u != 0x3ff1c60000000000) ERR; */ + + /* Close the file again. */ + if (nc_close(ncid)) ERR; + } + } + SUMMARIZE_ERR; FINAL_RESULTS;