GLPK output formats - linear-programming

Question

I am new to GLPK, so my apologies in advance if I'm missing something simple!
I have a largeish LP that I am feeding through GLPK to model an energy market. I'm running the following command line to GLPK to process this:
winglpk-4.65\glpk-4.65\w64\glpsol --lp problem.lp --data ExampleDataFile.dat --output results2.txt
When I open the resulting text file I can see the outputs, which all look sensible. I have one big problem: each record is split over two rows, making it very difficult to clean the file. See an extract below:
No. Row name St Activity Lower bound Upper bound Marginal
------ ------------ -- ------------- ------------- ------------- -------------
1 c_e_SpecifiedDemand(UTOPIA_CSV_ID_1990)_
NS 0 0 = < eps
2 c_e_SpecifiedDemand(UTOPIA_CSV_ID_1991)_
NS 0 0 = < eps
3 c_e_SpecifiedDemand(UTOPIA_CSV_ID_1992)_
NS 0 0 = < eps
4 c_e_SpecifiedDemand(UTOPIA_CSV_ID_1993)_
NS 0 0 = < eps
5 c_e_SpecifiedDemand(UTOPIA_CSV_ID_1994)_
NS 0 0 = < eps
6 c_e_SpecifiedDemand(UTOPIA_CSV_ID_1995)_
NS 0 0 = < eps
7 c_e_SpecifiedDemand(UTOPIA_CSV_ID_1996)_
NS 0 0 = < eps
8 c_e_SpecifiedDemand(UTOPIA_CSV_ID_1997)_
NS 0 0 = < eps
9 c_e_SpecifiedDemand(UTOPIA_CSV_ID_1998)_
NS 0 0 = < eps
10 c_e_SpecifiedDemand(UTOPIA_CSV_ID_1999)_
NS 0 0 = < eps
11 c_e_SpecifiedDemand(UTOPIA_CSV_ID_2000)_
NS 0 0 = < eps
12 c_e_SpecifiedDemand(UTOPIA_CSV_ID_2001)_
NS 0 0 = < eps
13 c_e_SpecifiedDemand(UTOPIA_CSV_ID_2002)_
NS 0 0 = < eps
14 c_e_SpecifiedDemand(UTOPIA_CSV_ID_2003)_
NS 0 0 = < eps
15 c_e_SpecifiedDemand(UTOPIA_CSV_ID_2004)_
NS 0 0 = < eps
I would be very grateful of any suggestions for either:
How I can get each record in the output text file onto a single row, or
Ideas on how to clean / post-process the existing text file output.
I'm sure I'm missing something simple here, but the output is in a very unhelpful format at the moment!
Thanks!

Answer 1

I wrote a Python parser for the GLPK output file. It is not beautiful and not save (try-catch) but it is working (for pure simplex problems).
You can call it on output file:
outp = GLPKOutput('myoutputfile')
print(outp)
val1 = outp.getCol('mycolvar','Activity')
val2 = outp.getRow('myrowname','Upper_bound') # row names should be defined
The class is as follows:
class GLPKOutput:
def __init__(self,filename):
self.rows = {}
self.columns = {}
self.nRows = 0
self.nCols = 0
self.nNonZeros = 0
self.Status = ""
self.Objective = ""
self.rowHeaders = []
self.rowIdx = {}
self.rowWidth = []
self.Rows = []
self.hRows = {}
self.colHeaders = []
self.colIdx = {}
self.colWidth = []
self.Cols = []
self.hCols = {}
self.wcols = ['Activity','Lower_bound','Upper bound','Marginal']
self.readFile(filename)
# split columns with weird line break
def smartSplit(self,line,type,job):
ret = []
line = line.rstrip()
if type == 'ROWS':
cols = len(self.rowHeaders)
idx = self.rowWidth
else:
cols = len(self.colHeaders)
idx = self.colWidth
if job == 'full':
start = 0
for i in range(cols):
stop = start+idx[i]+1
ret.append(line[start:stop].strip())
start = stop
elif job == 'part1':
entries = line.split()
ret = entries[0:2]
elif job == 'part2':
start = 0
for i in range(cols):
stop = start+idx[i]+1
ret.append(line[start:stop].strip())
start = stop
ret = ret[2:]
# print()
# print("SMART:",job,line.strip())
# print(" TO:",ret)
return ret
def readFile(self,filename):
fp = open(filename,"r")
lines = fp.readlines()
fp.close
i = 0
pos = "HEAD"
while pos == 'HEAD' and i<len(lines):
entries = lines[i].split()
if len(entries)>0:
if entries[0] == 'Rows:':
self.nRows = int(entries[1])
elif entries[0] == 'Columns:':
self.nCols = int(entries[1])
elif entries[0] == 'Non-zeros:':
self.nNonZeros = int(entries[1])
elif entries[0] == 'Status:':
self.Status = entries[1]
elif entries[0] == 'Objective:':
self.Objective = float(entries[3]) #' '.join(entries[1:])
elif re.search('Row name',lines[i]):
lines[i] = lines[i].replace('Row name','Row_name')
lines[i] = lines[i].replace('Lower bound','Lower_bound')
lines[i] = lines[i].replace('Upper bound','Upper_bound')
entries = lines[i].split()
pos = 'ROWS'
self.rowHeaders = entries
else:
pass
i+= 1
# formatting of row width
self.rowWidth = lines[i].split()
for k in range(len(self.rowWidth)): self.rowWidth[k] = len(self.rowWidth[k])
# print("Row Widths:",self.rowWidth)
i+= 1
READY = False
FOUND = False
while pos == 'ROWS' and i<len(lines):
if re.match('^\s*[0-9]+',lines[i]): # new line
if len(lines[i].split())>2: # no linebrak
entries = self.smartSplit(lines[i],pos,'full')
READY = True
else: # line break
entries = self.smartSplit(lines[i],pos,'part1')
READY = False
FOUND = True
else:
if FOUND and not READY: # second part of line
entries += self.smartSplit(lines[i],pos,'part2')
READY = True
FOUND = False
if READY:
READY = False
FOUND = False
# print("ROW:",entries)
if re.match('[0-9]+',entries[0]): # valid line with solution data
self.Rows.append(entries)
self.hRows[entries[1]] = len(self.Rows)-1
else:
print("wrong line format ...")
print(entries)
sys.exit()
elif re.search('Column name',lines[i]):
lines[i] = lines[i].replace('Column name','Column_name')
lines[i] = lines[i].replace('Lower bound','Lower_bound')
lines[i] = lines[i].replace('Upper bound','Upper_bound')
entries = lines[i].split()
pos = 'COLS'
self.colHeaders = entries
else:
pass #print("NOTHING: ",lines[i])
i+= 1
# formatting of row width
self.colWidth = lines[i].split()
for k in range(len(self.colWidth)): self.colWidth[k] = len(self.colWidth[k])
# print("Col Widths:",self.colWidth)
i+= 1
READY = False
FOUND = False
while pos == 'COLS' and i<len(lines):
if re.match('^\s*[0-9]+',lines[i]): # new line
if len(lines[i].split())>2: # no linebreak
entries = self.smartSplit(lines[i],pos,'full')
READY = True
else: # linebreak
entries = self.smartSplit(lines[i],pos,'part1')
READY = False
FOUND = True
else:
if FOUND and not READY: # second part of line
entries += self.smartSplit(lines[i],pos,'part2')
READY = True
FOUND = False
if READY:
READY = False
FOUND = False
# print("COL:",entries)
if re.match('[0-9]+',entries[0]): # valid line with solution data
self.Cols.append(entries)
self.hCols[entries[1]] = len(self.Cols)-1
else:
print("wrong line format ...")
print(entries)
sys.exit()
elif re.search('Karush-Kuhn-Tucker',lines[i]):
pos = 'TAIL'
else:
pass #print("NOTHING: ",lines[i])
i+= 1
for i,e in enumerate(self.rowHeaders): self.rowIdx[e] = i
for i,e in enumerate(self.colHeaders): self.colIdx[e] = i
def getRow(self,name,attr):
if name in self.hRows:
if attr in self.rowIdx:
try:
val = float(self.Rows[self.hRows[name]][self.rowIdx[attr]])
except:
val = self.Rows[self.hRows[name]][self.rowIdx[attr]]
return val
else:
return -1
def getCol(self,name,attr):
if name in self.hCols:
if attr in self.colIdx:
try:
val = float(self.Cols[self.hCols[name]][self.colIdx[attr]])
except:
val = self.Cols[self.hCols[name]][self.colIdx[attr]]
return val
else:
print("key error:",name,"not known ...")
return -1
def __str__(self):
retString = '\n'+"="*80+'\nSOLUTION\n'
retString += "nRows: "+str(self.nRows)+'/'+str(len(self.Rows))+'\n'
retString += "nCols: "+str(self.nCols)+'/'+str(len(self.Cols))+'\n'
retString += "nNonZeros: "+str(self.nNonZeros)+'\n'
retString += "Status: "+str(self.Status)+'\n'
retString += "Objective: "+str(self.Objective)+'\n\n'
retString += ' '.join(self.rowHeaders)+'\n'
for r in self.Rows: retString += ' # '.join(r)+' #\n'
retString += '\n'
retString += ' '.join(self.colHeaders)+'\n'
for c in self.Cols: retString += ' # '.join(r)+' #\n'
return retString