Raise informative error for float/integer exponentiation that yields … #12822
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| print(io, "a zero decimal (e.g. 2.0^-n instead of 2^-n), or write 1/x^n, float(x)^-n, or (x//1)^-n .") | ||
| elseif code[1] == :^ && (code[2] == symbol("promotion.jl") || code[2] == symbol("math.jl")) | ||
| println(io, "\nCannot raise an integer or float yielding a complex number. ") | ||
| print(io, "If x is the input number that should be raised to y, use (x+0im)^y or convert(Complex, x)^y .") |
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Complex(x) is simpler than convert. Maybe: "Replace x^y with (x+0im)^y, Complex(x)^y, or similar."
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Stylistically, it is weird that we are using multiple print calls here. Would be cleaner to replace this (and similar constructions above) with:
print(io, "\n ............",
"\n .......")
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@stevengj , thanks for the input. |
Raise informative error for float/integer exponentiation that yields …
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Hmm, this was technically not a bugfix; should I not have merged in the 0.4-pre cycle? Since it was just an improved error message, it seemed innocuous. |
| elseif (code[1] == :^ && code[2] == symbol("intfuncs.jl")) || code[1] == :power_by_squaring | ||
| println(io, "\nCannot raise an integer x to a negative power -n. Make x a float by adding") | ||
| print(io, "a zero decimal (e.g. 2.0^-n instead of 2^-n), or write 1/x^n, float(x)^-n, or (x//1)^-n") | ||
| println(io,"\n$(code[1]) will only return a complex result if called with a complex argument. ", |
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Hmm, this probably should have been print, not println; you added an extra newline to the output.
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@stevengj , actually that was the original design. I didn't introduce it. In fact, I'm not getting extraneous newlines comparing the output before and after your commit removing those println (e3d2cb7). Since I didn't notice that behavior, I didn't bother to change the old code.
Before
_/ |\__'_|_|_|\__'_| | Commit 732860a (0 days old master)
|__/ | x86_64-apple-darwin14.5.0
julia> log(-2)
ERROR: DomainError:
log will only return a complex result if called with a complex argument.
try log (complex(x))
in log at math.jl:139
julia> (-2.0)^(2.2)
ERROR: DomainError:
in ^ at math.jl:275After
_/ |\__'_|_|_|\__'_| | Commit e3d2cb7 (0 days old master)
|__/ | x86_64-apple-darwin14.5.0
julia> log(-2)
ERROR: DomainError:
log will only return a complex result if called with a complex argument. Try log (complex(x)).
in log at math.jl:139
julia> (-2.0)^(2.2)
ERROR: DomainError:
Exponentiation yielding a complex result requires a complex argument.
Replace x^y with (x+0im)^y, Complex(x)^y, or similar.
in ^ at math.jl:275
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Seems okay to me, I don't think this would break anything. |
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@felipenoris, the original code had |
…Complex
Same as #3024.
Deals with the following cases: