""" Functions for reading and writing Matlab mat-files. Based on the documentation of the mat-file format at www.mathworks.com/access/helpdesk/help/pdf_doc/matlab/matfile_format.pdf. """ from cvxopt.base import matrix, spmatrix from struct import pack, unpack, calcsize from math import ceil from time import ctime import zlib __all__ = ['read', 'write'] def read(f): """ Returns a dictionary with the contents of the mat-file f. The elements in the dictionary are Matlab name/variable pairs. Matlab variables of a type that is not supported (for example, arrays of dimension higher than two) are replaced by strings. """ def decode_str(s, E): TYPES = ['','b','B','h','H','i','i','f','','d'] CLASS = ['Cell array','Structure','Object'] def get_tag(s): (utype, ulgt) = unpack("%sii"%E, s[:8]) if (utype >> 16): ulgt, utype = (utype >> 16), (utype & 0xffff) offs, inc = 4, 8*((4+ulgt+7)/8) else: offs, inc = 8, 8*((8+ulgt+7)/8) return (utype, ulgt, offs, inc) datatype, numbytes = unpack("%sii"%E,s[:8]) idx = 8 if datatype == 14: utype, ulgt, flags = unpack("%siii"%E,s[idx:idx+12]) flags, cls = (flags >> 8) & 0xff, flags & 0xff nzmax = unpack("i",s[idx+12:idx+16])[0] # only for sparse idx += 16 # dimension array (utype, ulgt, offs, inc) = get_tag(s[idx:idx+8]) dims = unpack("%s%ii"%(E,ulgt/4), s[idx+offs:idx+offs+ulgt]) idx += inc if len(dims)>2: return (name, "array with dimensions %s not implemented" %dims) # array name (utype, ulgt, offs, inc) = get_tag(s[idx:idx+8]) name = unpack("%is"%ulgt, s[idx+offs:idx+offs+ulgt])[0] idx += inc if cls in [0,1,2,3]: return (name, CLASS[cls-1]+" not implemented") if cls == 4: (utype, ulgt, offs, inc) = get_tag(s[idx:idx+8]) return (name,unpack("%is"%ulgt, s[idx+offs:idx+offs+ulgt])[0]) # sparse data elif cls == 5: if (flags & 8): return (name, "complex sparse not implemented") (utype, ulgt, offs, inc) = get_tag(s[idx:idx+8]) ri = unpack("%ii"%(ulgt/4), s[idx+offs:idx+offs+ulgt]) idx += inc (utype, ulgt, offs, inc) = get_tag(s[idx:idx+8]) cp = unpack("%ii"%(ulgt/4), s[idx+offs:idx+offs+ulgt]) idx += inc # real part (utype, ulgt, offs, inc) = get_tag(s[idx:idx+8]) tmp = "%s%i%s" %(E,ulgt/calcsize(TYPES[utype]),TYPES[utype]) pr = unpack(tmp, s[idx+offs:idx+offs+ulgt]) idx += inc # convert CCS to IJV V = matrix(list(pr)) I = matrix(list(ri[:len(V)]),tc='i') J = matrix(0, size=(len(I),1), tc='i') for i in xrange(1,len(cp)): J[cp[i-1]:cp[i]]=i-1 return (name, spmatrix(V,I,J,size=dims)) # dense matrix # real part (utype, ulgt, offs, inc) = get_tag(s[idx:idx+8]) tmp = "%s%i%s" %(E,ulgt/calcsize(TYPES[utype]),TYPES[utype]) pr = unpack(tmp, s[idx+offs:idx+offs+ulgt]) idx += inc if cls in [6,7]: tc = 'd' else: tc = 'i' pr = matrix(list(pr), dims, tc) # imaginary part if (flags & 8): (utype, ulgt, offs, inc) = get_tag(s[idx:idx+8]) tmp = "%s%i%s" %(E,ulgt/calcsize(TYPES[utype]),TYPES[utype]) pi = unpack(tmp, s[idx+offs:idx+offs+ulgt]) pi = matrix(list(pi), dims, tc) return (name, pr+1J*pi) else: return (name, pr) elif datatype == 15: return decode_str(zlib.decompress(s[8:]), E) else: raise ValueError, "unexpected datatype" # # Start of read # s = open(f,'rb').read() E = '<' endian = unpack("%s2s"%E,s[126:128])[0] if endian == 'MI': E = '>' matstr, subsys, version = unpack("%s116s8sH"%E,s[:126]) if version != 0x0100: raise ValueError, "not a level 5 MAT file" lgt = 128 D = {} while lgt < len(s): datatype, numbytes = unpack("%sii"%E,s[lgt:lgt+8]) (name, var) = decode_str(s[lgt:lgt+8+numbytes],E) D[name] = var lgt += numbytes + 8 return D def write(f, var): """ Writes the dictionary var to the mat-file f. var is a dictionary with name/variable pairs. The name is the name of the Matlab variable created in the mat-file. The type of the variable must be matrix, spmatrix, string, int, float or complex. """ def encode_obj(name, val): def encode_str(var, id): if len(var) <= 4: return pack("HH4s",id,len(var),var) else: l = int(8*ceil(len(var)/8.0)) return pack("ii%is"%l,id,len(var),var) def encode_cvxopt_mtx(val): if val.typecode == 'i': s = pack("ii",5,len(val)*4) for i in xrange(len(val)): s += pack("i", val[i]) npad = 8*int(ceil(4*len(val)/8.0)) s += (npad-len(val)*4)*'\0' elif val.typecode == 'd': s = pack("ii",9,len(val)*8) for i in xrange(len(val)): s += pack("d", val[i]) else: s = pack("ii",9,len(val)*8) for i in xrange(len(val)): s += pack("d", val[i].real) s += pack("ii",9,len(val)*8) for i in xrange(len(val)): s += pack("d", val[i].imag) return s if isinstance(val, matrix): flags = 8*(val.typecode == 'z') if val.typecode == 'i': cls = 12 else: cls = 6 s = pack("iiixxxx", 6, 8, flags*256+cls) s += pack("iiii", 5, 8, val.size[0], val.size[1]) s += encode_str(name,1) s += encode_cvxopt_mtx(val) elif isinstance(val, spmatrix): flags, cls, nzmax = 0, 5, len(val) I, J, V = val.I, val.J, val.V cp = matrix(0,(val.size[1]+1,1),tc='i') for i in xrange(len(J)): cp[J[i]+1] += 1 for i in xrange(val.size[1]): cp[i+1] += cp[i] s = pack("iiii", 6, 8, flags*256+cls, nzmax) s += pack("iiii", 5, 8, val.size[0], val.size[1]) s += encode_str(name,1) s += encode_cvxopt_mtx(I) s += encode_cvxopt_mtx(cp) s += encode_cvxopt_mtx(V) elif isinstance(val, str): flags, cls = 0, 4 s = pack("iiixxxx", 6, 8, flags*256+cls) s += pack("iiii", 5, 8, 1, len(val)) s += encode_str(name,1) s += encode_str(val,16) elif isinstance(val, int): return encode_obj(name, matrix(val, tc='i')) elif isinstance(val, float): return encode_obj(name, matrix(val, tc='d')) elif isinstance(val, complex): return encode_obj(name, matrix(val, tc='z')) else: raise TypeError, "%s not supported" %type(val) s = pack("ii",14,len(s)) + s #s = zlib.compress(s, 9) #s = pack("ii",15,len(s)) + s return s # # start of write # IDstr = "MATLAB 5.0 MAT-file, Created by CVXOPT on " + ctime() endian = 256*ord('M')+ord('I') s = pack("116s8sHH",IDstr,' ',0x0100,endian) for name in var.keys(): s2 = encode_obj(name, var[name]) s += s2 open(f,'wb').write(s)