Reference state not correctly applied for mixtures

[ianhbell]

From #710: The setting of reference states does not work correctly when fluid names are passed to the REFPROP function. The reference state is not set. Example:

import os 
import ctREFPROP.ctREFPROP as ct 

root = '/Users/ihb/REFPROP10'
assert(os.path.exists(root))
RP = ct.REFPROPFunctionLibrary(root+'/librefprop.dylib')
RP.SETPATHdll(root)

res = RP.REFPROPdll("", "FLAGS", "SETREF", 0, 0, 2, 0, 0, [])
print(res.ierr, res.herr)
assert(res.ierr == 0)

r0 = RP.REFPROPdll("R32;R125|0.3;0.7", "PS", "H", RP.MOLAR_SI, 0, 0, 10, 110, [])
r1 = RP.REFPROPdll("R32;R125|0.3;0.7", "PS", "H", RP.MOLAR_SI, 0, 0, 10, 110, [])
print('expected value of 23643.99395000000004075 ')
print(r0.Output[0], r1.Output[0], r1.herr, r0.herr)

yielding

expected value of 23643.99395000000004075 
23643.993946887913 -9999990.0 [PSFLSH error 248] Single-phase iteration did not converge for P = 10.0000 MPa and S = 110.000 J/mol-K. 

so the first call is ok, the second one is not. Calling SETREF again in between the calls helps:

import os 
import ctREFPROP.ctREFPROP as ct 

root = '/Users/ihb/REFPROP10'
assert(os.path.exists(root))
RP = ct.REFPROPFunctionLibrary(root+'/librefprop.dylib')
RP.SETPATHdll(root)

res = RP.REFPROPdll("", "FLAGS", "SETREF", 0, 0, 2, 0, 0, [])
print(res.ierr, res.herr)
assert(res.ierr == 0)

r0 = RP.REFPROPdll("R32;R125|0.3;0.7", "PS", "H", RP.MOLAR_SI, 0, 0, 10, 110, [])
res = RP.REFPROPdll("", "FLAGS", "SETREF", 0, 0, 2, 0, 0, [])
r1 = RP.REFPROPdll("R32;R125|0.3;0.7", "PS", "H", RP.MOLAR_SI, 0, 0, 10, 110, [])
print('expected value of 23643.99395000000004075 ')
print(r0.Output[0], r1.Output[0], r1.herr, r0.herr)

yielding the correct answer of

0 
expected value of 23643.99395000000004075 
23643.993946887913 23643.993946887913  

but the second SETREF should not be required because the flag is supposed to stay on:

[ianhbell]

Breaking up the steps works in all versions:

import os 
import ctREFPROP.ctREFPROP as ct 

root = '/Users/ihb/REFPROP10'
assert(os.path.exists(root))
RP = ct.REFPROPFunctionLibrary(root+'/librefprop.dylib')
RP.SETPATHdll(root)

print(RP.FLAGSdll("SETREF", 999))

z = [0.3, 0.7]
RP.SETFLUIDSdll("R32*R125")
RP.SETREFdll('',2,z,-1,-1,-1,-1)
r0 = RP.REFPROPdll("", "PS", "H", RP.MOLAR_SI, 0, 0, 10, 110, z)
r1 = RP.REFPROPdll("", "PS", "H", RP.MOLAR_SI, 0, 0, 10, 110, z)

print('expected value of 23643.99395000000004075 ')
print(r0.Output[0], r1.Output[0], r1.herr, r0.herr)

yielding

FLAGSdlloutput(kFlag=0, ierr=0, herr='')
expected value of 23643.99395000000004075 
23643.993946887913 23643.993946887913