Prior to this fix, pow(1.5, inf) and pow(0.5, -inf) (among other things)
would incorrectly raise a ValueError, because the result is inf with the
first argument being finite. This commit fixes this by allowing the result
to be infinite if the first or second (or both) argument is infinite.
This fix doesn't affect the other three math functions that have two
arguments:
- atan2 never returns inf, so always fails isinf(ans)
- copysign returns inf only if the first argument x is inf, so will never
reach the isinf(y) check
- fmod never returns inf, so always fails isinf(ans)
Signed-off-by: Damien George <damien@micropython.org>
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>
Formerly, py/formatfloat would print whole numbers inaccurately with
nonzero digits beyond the decimal place. This resulted from its strategy
of successive scaling of the argument by 0.1 which cannot be exactly
represented in floating point. The change in this commit avoids scaling
until the value is smaller than 1, so all whole numbers print with zero
fractional part.
Fixes issue #4212.
Signed-off-by: Dan Ellis dan.ellis@gmail.com
This commit simplifies mp_obj_get_complex_maybe() by first calling
mp_obj_get_float_maybe() to handle the cases corresponding to floats.
Only if that fails does it attempt to extra a full complex number.
This reduces code size and also means that mp_obj_get_complex_maybe() now
supports user-defined classes defining __float__; in particular this allows
user-defined classes to be used as arguments to cmath-module function.
Furthermore, complex_make_new() can now be simplified to directly call
mp_obj_get_complex(), instead of mp_obj_get_complex_maybe() followed by
mp_obj_get_float(). This also improves error messages from complex with
an invalid argument, it now raises "can't convert <type> to complex" rather
than "can't convert <type> to float".
Signed-off-by: Damien George <damien@micropython.org>
Prior to this commit, complex("j") would return 0j, and complex("nanj")
would return nan+0j. This commit makes sure "j" is tested for after
parsing the number (nan, inf or a decimal), and also supports the case of
"j" on its own.
Signed-off-by: Damien George <damien@micropython.org>
2.5 can be represented correctly in object representation C, but 2.3 cannot
(it is slightly truncated).
Signed-off-by: Damien George <damien@micropython.org>
Prior to this commit, pow(-2, float('nan')) would return (nan+nanj), or
raise an exception on targets that don't support complex numbers. This is
fixed to return simply nan, as CPython does.
Signed-off-by: Damien George <damien@micropython.org>
This is consistent with the other 'micro' modules and allows implementing
additional features in Python via e.g. micropython-lib's sys.
Note this is a breaking change (not backwards compatible) for ports which
do not enable weak links, as "import sys" must now be replaced with
"import usys".
Updating to Black v20.8b1 there are two changes that affect the code in
this repository:
- If there is a trailing comma in a list (eg [], () or function call) then
that list is now written out with one line per element. So remove such
trailing commas where the list should stay on one line.
- Spaces at the start of """ doc strings are removed.
Signed-off-by: Damien George <damien@micropython.org>
So they can be skipped if __rOP__'s are not supported on the target. Also
fix the typo in the complex_special_methods.py filename.
Signed-off-by: Damien George <damien@micropython.org>
This allows complex binary operations to fail gracefully with unsupported
operation rather than raising an exception, so that special methods work
correctly.
Signed-off-by: Damien George <damien@micropython.org>
Older implementations deal with infinity/negative zero incorrectly. This
commit adds generic fixes that can be enabled by any port that needs them,
along with new tests cases.
For combinations of certain versions of glibc and gcc the definition of
fpclassify always takes float as argument instead of adapting itself to
float/double/long double as required by the C99 standard. At the time of
writing this happens for instance for glibc 2.27 with gcc 7.5.0 when
compiled with -Os and glibc 3.0.7 with gcc 9.3.0. When calling fpclassify
with double as argument, as in objint.c, this results in an implicit
narrowing conversion which is not really correct plus results in a warning
when compiled with -Wfloat-conversion. So fix this by spelling out the
logic manually.
When the unix and windows ports use MICROPY_FLOAT_IMPL_FLOAT instead of
MICROPY_FLOAT_IMPL_DOUBLE, the test output has for example
complex(-0.15052, 0.34109) instead of the expected
complex(-0.15051, 0.34109).
Use one decimal place less for the output printing to fix this.
Since automatically formatting tests with black, we have lost one line of
code coverage. This adds an explicit test to ensure we are testing the
case that is no longer covered implicitly.
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.
As per PEP 485, this function appeared in for Python 3.5. Configured via
MICROPY_PY_MATH_ISCLOSE which is disabled by default, but enabled for the
ports which already have MICROPY_PY_MATH_SPECIAL_FUNCTIONS enabled.
Nan and inf (signed and unsigned) are also handled correctly by using
signbit (they were also handled correctly with "val<0", but that didn't
handle -0.0 correctly). A test case is added for this behaviour.
This commit adds the math.factorial function in two variants:
- squared difference, which is faster than the naive version, relatively
compact, and non-recursive;
- a mildly optimised recursive version, faster than the above one.
There are some more optimisations that could be done, but they tend to take
more code, and more storage space. The recursive version seems like a
sensible compromise.
The new function is disabled by default, and uses the non-optimised version
by default if it is enabled. The options are MICROPY_PY_MATH_FACTORIAL
and MICROPY_OPT_MATH_FACTORIAL.
Printing of uPy floats can differ by the floating-point precision on
different architectures (eg 64-bit vs 32-bit x86), so it's not possible to
using printing of floats in some parts of this test. Instead we can just
check for equivalence with what is known to be the correct answer.
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.
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.
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.
Float parsing (both single and double precision) may have a relative error
of order the floating point precision, so adjust tests to take this into
account by not printing all of the digits of the answer.
Prior to this patch, a float literal that was close to subnormal would
have a loss of precision when parsed. The worst case was something like
float('10000000000000000000e-326') which returned 0.0.
This patch improves parsing of floating point numbers by converting all the
digits (integer and fractional) together into a number 1 or greater, and
then applying the correct power of 10 at the very end. In particular the
multiple "multiply by 0.1" operations to build a fraction are now combined
together and applied at the same time as the exponent, at the very end.
This helps to retain precision during parsing of floats, and also includes
a check that the number doesn't overflow during the parsing. One benefit
is that a float will have the same value no matter where the decimal point
is located, eg 1.23 == 123e-2.
This patch changes how most of the plain math functions are implemented:
there are now two generic math wrapper functions that take a pointer to a
math function (like sin, cos) and perform the necessary conversion to and
from MicroPython types. This helps to reduce code size. The generic
functions can also check for math domain errors in a generic way, by
testing if the result is NaN or infinity combined with finite inputs.
The result is that, with this patch, all math functions now have full
domain error checking (even gamma and lgamma) and code size has decreased
for most ports. Code size changes in bytes for those with the math module
are:
unix x64: -432
unix nanbox: -792
stm32: -88
esp8266: +12
Tests are also added to check domain errors are handled correctly.
This returns a complex number, following CPython behaviour. For ports that
don't have complex numbers enabled this will raise a ValueError which gives
a fail-safe for scripts that were written assuming complex numbers exist.
IEEE floating point is specified such that a comparison of NaN with itself
returns false, and Python respects these semantics. This patch makes uPy
also have these semantics. The fix has a minor impact on the speed of the
object-equality fast-path, but that seems to be unavoidable and it's much
more important to have correct behaviour (especially in this case where
the wrong answer for nan==nan is silently returned).
