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added more documentation, also started on test code for type conversion

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This commit is contained in:
Edward Hartnett 2021-08-29 22:34:14 -06:00
parent f5e2926f02
commit 5d1aa2a926
2 changed files with 71 additions and 1 deletions
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12
libdispatch/dvar.c
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@ -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

60
nc_test4/tst_quantize.c
View File

@ -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;