Package doesn't work with 32-bit platforms

[rickhg12hs]

$ ./julia -E 'versioninfo();println(Pkg.installed("SIUnits"));Pkg.test("SIUnits")'
Julia Version 0.4.0-dev+118
Commit a44ea2a (2014-08-14 02:49 UTC)
Platform Info:
  System: Linux (i686-redhat-linux)
  CPU: Genuine Intel(R) CPU           T2250  @ 1.73GHz
  WORD_SIZE: 32
  BLAS: libopenblas (DYNAMIC_ARCH NO_AFFINITY Banias)
  LAPACK: libopenblas
  LIBM: libopenlibm
  LLVM: libLLVM-3.3
0.0.2+
INFO: Testing SIUnits
ERROR: `+` has no method matching +(::(Int32,Int32,Int32,Int32,Int32,Int32,Int32), ::(Int32,Int32,Int32,Int32,Int32,Int32,Int32))
 in * at promotion.jl:159
 in include at ./boot.jl:245
 in include_from_node1 at ./loading.jl:128
 in reload_path at loading.jl:152
 in _require at loading.jl:67
 in require at loading.jl:51
 in include at ./boot.jl:245
 in include_from_node1 at loading.jl:128
 in process_options at ./client.jl:285
 in _start at ./client.jl:354
 in _start_3B_1688 at /usr/local/src/julia/julia/usr/bin/../lib/julia/sys.so
while loading /home/rick/.julia/v0.4/SIUnits/src/SIUnits.jl, in expression starting on line 318
while loading /home/rick/.julia/v0.4/SIUnits/test/runtests.jl, in expression starting on line 1

===============================[ ERROR: SIUnits ]===============================

failed process: Process(`/usr/local/src/julia/julia/usr/bin/julia /home/rick/.julia/v0.4/SIUnits/test/runtests.jl`, ProcessExited(1)) [1]

================================================================================
INFO: No packages to install, update or remove
ERROR: SIUnits had test errors
 in error at error.jl:21
 in test at pkg/entry.jl:711
 in anonymous at pkg/dir.jl:28
 in cd at ./file.jl:20
 in cd at pkg/dir.jl:28
 in test at pkg.jl:67
 in process_options at ./client.jl:219
 in _start at ./client.jl:354
 in _start_3B_1688 at /usr/local/src/julia/julia/usr/bin/../lib/julia/sys.so

[timholy]

I bet the problem is here. @rickhg12hs, can you change that, test, and if it works submit a PR?

[rickhg12hs]

It looks like there are more problems for 32-bit platforms. E.g., const Yotta (and others) will overflow/wrap with Int32s.

using SIUnits doesn't even work at the moment.

julia> versioninfo()
Julia Version 0.4.0-dev+492
Commit beca3e4 (2014-09-06 19:43 UTC)
Platform Info:
  System: Linux (i686-redhat-linux)
  CPU: Genuine Intel(R) CPU           T2250  @ 1.73GHz
  WORD_SIZE: 32
  BLAS: libopenblas (DYNAMIC_ARCH NO_AFFINITY Banias)
  LAPACK: libopenblas
  LIBM: libopenlibm
  LLVM: libLLVM-3.3

julia> using SIUnits
Warning: New definition 
    convert(Type{SIQuantity{T,m,kg,s,A,K,mol,cd}},T) at /home/rick/.julia/v0.4/SIUnits/src/SIUnits.jl:102
is ambiguous with: 
    convert(Type{T<:Number},Period) at dates/periods.jl:23.
To fix, define 
    convert(Type{SIQuantity{_<:Period,m,kg,s,A,K,mol,cd}},_<:Period)
before the new definition.
Warning: New definition 
    convert(Type{SIQuantity{T,m,kg,s,A,K,mol,cd}},S) at /home/rick/.julia/v0.4/SIUnits/src/SIUnits.jl:103
is ambiguous with: 
    convert(Type{T<:Number},Period) at dates/periods.jl:23.
To fix, define 
    convert(Type{SIQuantity{T,m,kg,s,A,K,mol,cd}},_<:Period)
before the new definition.
Warning: New definition 
    convert(Type{SIQuantity{T,m,kg,s,A,K,mol,cd}},S) at /home/rick/.julia/v0.4/SIUnits/src/SIUnits.jl:108
is ambiguous with: 
    convert(Type{T<:Number},Period) at dates/periods.jl:23.
To fix, define 
    convert(Type{SIQuantity{T,m,kg,s,A,K,mol,cd}},_<:Period)
before the new definition.
ERROR: `+` has no method matching +(::(Int32,Int32,Int32,Int32,Int32,Int32,Int32), ::(Int32,Int32,Int32,Int32,Int32,Int32,Int32))
 in * at promotion.jl:159
 in include at ./boot.jl:246
 in include_from_node1 at ./loading.jl:128
 in reload_path at loading.jl:152
 in _require at loading.jl:67
 in require at loading.jl:51
while loading /home/rick/.julia/v0.4/SIUnits/src/SIUnits.jl, in expression starting on line 292

[rickhg12hs]

Actually, do the more "extreme" constants even work on a 64-bit platform?

const Zetta      = (10^21)SIPrefix
const Yotta      = (10^24)SIPrefix

and

const Zepto      = (1//10^21)SIPrefix
const Yocto      = (1//10^24)SIPrefix

[timholy]

Hmm, looks like not. I may have been the one to add those. Oops.

I suppose we could make them BigInts, but alternatively we could just delete them. Thoughts?

[Keno]

The overflow situation is pretty bad. Nowadays when doing exploratory calculations I mostly use bigints and bigfloats to avoid bad answers. This of course not great for production. We probably need some sort of support for storing the order of magnitude in the type.

[rickhg12hs]

How about Int128's?

Need to make it all work on different platforms too.

[tomasaschan]

One way to store the type information in SIPrefix would be to make the type parametric on the exponent, i.e.

const Yotta = (10^24)SIPrefix

becomes

const Yotta = 1*SIPrefix{24}

Of course we'd have to implement some special arithmetic for SIPrefixes to handle this, but at least we should be able to avoid overflows in most cases. It's probably also possible to define normalize(siq::SIQuantity) to store the OOM of siq in the type instead of the number (although I'm not sure it's a good idea - I haven't thought very carefully about rounding errors that might be introduced, for example...).

[stevengj]

A parametric SIPrefix, analogous to SIQuantity, makes the most sense to me.

[tkelman]

cc me, note to re-enable tests that depend on SIUnits in Images.jl for 32 bit systems when this is fixed ref https://github.com/timholy/Images.jl/pull/243#issuecomment-68942440