Groups   212 of 99+      julia-users › Problems understanding the usage of SharedArrays 3 posts by 3 authors      Nils Gudat    1 9 15   Sorry for asking the umptiest question on parallelization, but I can't seem to get even the most basic calculations to run, so here's hoping someone can enlighten me. I'd like to make an interpolant created with Dierckx available on all my processors. I figured this would be possible using SharedArrays in the following way:  addprocs 3    everywhere using Dierckx  xgrid   linspace 0.1, 100.0, 200   f_val    xgrid i   -0.25  for i in length xgrid    convert SharedArray, xgrid  convert SharedArray, f_val    everywhere interpolant   Spline1D xgrid, f_val    However, this attempt fails with two errors  or six, two for each core :  Spline1D has not method matching Spline1D ::SharedArray Float64, 1 , ::SharedArray Float64, 1    and  xgrid_irr not defined  I have a question on each: 1. How can I use SharedArrays in functions that don't have a method for them?  2. Why would xgrid not be defined on the other cores? My understanding from reading the SharedArray part of the documentation was that their whole purpose is to make an array available to all cores?  Any hints or tips would be greatly appreciated!     Tim Holy    1 9 15   1. You  or someone  needs to write those methods. Since the Spline1D function  is defined in the Dierckx package, that's where the SharedArray version should  go, too  if you don't just maintain it on your own .   2. After      convert SharedArray, xgrid   xgrid will still be an ordinary array. You've not captured the output of the  convert function.   --Tim   On Friday, January 09, 2015 08:33:20 AM Nils Gudat wrote:    Sorry for asking the umptiest question on parallelization, but I can't seem    to get even the most basic calculations to run, so here's hoping someone    can enlighten me.    I'd like to make an interpolant created with Dierckx available on all my    processors. I figured this would be possible using SharedArrays in the    following way:       addprocs 3         everywhere using Dierckx       xgrid   linspace 0.1, 100.0, 200        f_val    xgrid i   -0.25  for i in length xgrid         convert SharedArray, xgrid     convert SharedArray, f_val         everywhere interpolant   Spline1D xgrid, f_val           However, this attempt fails with two errors  or six, two for each core :       Spline1D has not method matching Spline1D ::SharedArray Float64, 1 ,       ::SharedArray Float64, 1         and       xgrid_irr not defined       I have a question on each:    1. How can I use SharedArrays in functions that don't have a method for    them?    2. Why would xgrid not be defined on the other cores? My understanding from    reading the SharedArray part     http:  julia.readthedocs.org en latest manual parallel-computing  shared-ar    rays-experimental  of the documentation was that their whole purpose is to       Kyle Barbary    1 9 15   Hi Nils,  We could add a SharedArray method to the Dierckx methods as Tim suggests, perhaps by changing the signatures from Vector Float64  to Union Vector Float64 , SharedArray Float64, 1  .  I’ve never really used SharedArrays myself, but an easier option might be to use the sdata function. For example, the following works for me:  xgrid   convert SharedArray, linspace 0.1, 100., 200    fval   convert SharedArray, Float64 xgrid i   -0.25  for i in 1:length xgrid     spl   Spline1D sdata xgrid , sdata fval   Best, Kyle