circuitpython/tests/float/float_format.py

# test float formatting

# general rounding
for val in (116, 1111, 1234, 5010, 11111):
    print("%.0f" % val)
    print("%.1f" % val)
    print("%.3f" % val)

# make sure rounding is done at the correct precision
for prec in range(8):
    print(("%%.%df" % prec) % 6e-5)

# check certain cases that had a digit value of 10 render as a ":" character
print("%.2e" % float("9" * 51 + "e-39"))
print("%.2e" % float("9" * 40 + "e-21"))

# check a case that would render negative digit values, eg ")" characters
# the string is converted back to a float to check for no illegal characters
float("%.23e" % 1e-80)

# Check a problem with malformed "e" format numbers on the edge of 1.0e-X.
for r in range(38):
    s = "%.12e" % float("1e-" + str(r))
    # It may format as 1e-r, or 9.999...e-(r+1), both are OK.
    # But formatting as 0.999...e-r is NOT ok.
    if s[0] == "0":
        print("FAIL:", s)
py/formatfloat: Fix rounding of %f format with edge-case FP values. Prior to this patch the %f formatting of some FP values could be off by up to 1, eg '%.0f' % 123 would return "122" (unix x64). Depending on the FP precision (single vs double) certain numbers would format correctly, but others wolud not. This patch should fix all cases of rounding for %f. 2018-02-28 23:47:17 -05:00			`# test float formatting`

			`# general rounding`
			`for val in (116, 1111, 1234, 5010, 11111):`
tests: Format all Python code with black, except tests in basics subdir. This adds the Python files in the tests/ directory to be formatted with ./tools/codeformat.py. The basics/ subdirectory is excluded for now so we aren't changing too much at once. In a few places `# fmt: off`/`# fmt: on` was used where the code had special formatting for readability or where the test was actually testing the specific formatting. 2020-03-22 22:26:08 -04:00			`print("%.0f" % val)`
			`print("%.1f" % val)`
			`print("%.3f" % val)`
py/formatfloat: Fix rounding of %f format with edge-case FP values. Prior to this patch the %f formatting of some FP values could be off by up to 1, eg '%.0f' % 123 would return "122" (unix x64). Depending on the FP precision (single vs double) certain numbers would format correctly, but others wolud not. This patch should fix all cases of rounding for %f. 2018-02-28 23:47:17 -05:00
			`# make sure rounding is done at the correct precision`
			`for prec in range(8):`
tests: Format all Python code with black, except tests in basics subdir. This adds the Python files in the tests/ directory to be formatted with ./tools/codeformat.py. The basics/ subdirectory is excluded for now so we aren't changing too much at once. In a few places `# fmt: off`/`# fmt: on` was used where the code had special formatting for readability or where the test was actually testing the specific formatting. 2020-03-22 22:26:08 -04:00			`print(("%%.%df" % prec) % 6e-5)`
py/formatfloat: Fix case where floats could render with a ":" character. Prior to this patch, some architectures (eg unix x86) could render floats with a ":" character in them, eg 1e+39 would come out as ":e+38" (":" is just after "9" in ASCII so this is like 10e+38). This patch fixes some of these cases. 2018-03-01 00:02:59 -05:00
			`# check certain cases that had a digit value of 10 render as a ":" character`
tests: Format all Python code with black, except tests in basics subdir. This adds the Python files in the tests/ directory to be formatted with ./tools/codeformat.py. The basics/ subdirectory is excluded for now so we aren't changing too much at once. In a few places `# fmt: off`/`# fmt: on` was used where the code had special formatting for readability or where the test was actually testing the specific formatting. 2020-03-22 22:26:08 -04:00			`print("%.2e" % float("9" * 51 + "e-39"))`
			`print("%.2e" % float("9" * 40 + "e-21"))`
py/formatfloat: Fix case where floats could render with negative digits. Prior to this patch, some architectures (eg unix x86) could render floats with "negative" digits, like ")". For example, '%.23e' % 1e-80 would come out as "1.0000000000000000/)/(,*0e-80". This patch fixes the known cases. 2018-03-01 01:00:02 -05:00
			`# check a case that would render negative digit values, eg ")" characters`
			`# the string is converted back to a float to check for no illegal characters`
tests: Format all Python code with black, except tests in basics subdir. This adds the Python files in the tests/ directory to be formatted with ./tools/codeformat.py. The basics/ subdirectory is excluded for now so we aren't changing too much at once. In a few places `# fmt: off`/`# fmt: on` was used where the code had special formatting for readability or where the test was actually testing the specific formatting. 2020-03-22 22:26:08 -04:00			`float("%.23e" % 1e-80)`
py/formatfloat: Use pow(10, e) instead of pos/neg_pow lookup tables. Rework the conversion of floats to decimal strings so it aligns precisely with the conversion of strings to floats in parsenum.c. This is to avoid rendering 1eX as 9.99999eX-1 etc. This is achieved by removing the power- of-10 tables and using pow() to compute the exponent directly, and that's done efficiently by first estimating the power-of-10 exponent from the power-of-2 exponent in the floating-point representation. Code size is reduced by roughly 100 to 200 bytes by this commit. Signed-off-by: Dan Ellis <dan.ellis@gmail.com> 2022-07-28 10:49:18 -04:00
			`# Check a problem with malformed "e" format numbers on the edge of 1.0e-X.`
			`for r in range(38):`
			`s = "%.12e" % float("1e-" + str(r))`
			`# It may format as 1e-r, or 9.999...e-(r+1), both are OK.`
			`# But formatting as 0.999...e-r is NOT ok.`
			`if s[0] == "0":`
			`print("FAIL:", s)`