test_matrix.php
  mi[0][0]=1

mi[0][1]=0

mi[0][2]=0

mi[1][0]=0

mi[1][1]=1

mi[1][2]=0

mi[2][0]=0

mi[2][1]=0

mi[2][2]=1

a[0][0]=1.5

a[0][1]=2.7

a[0][2]=3.9

a[1][0]=2.2

a[1][1]=3.1

a[1][2]=1.5

a[2][0]=3.4

a[2][1]=2.6

a[2][2]=1.2

b[0]=2.1

b[1]=3.2

b[2]=4.3

bbb[0][0]=1.5

bbb[0][1]=2.7

bbb[0][2]=3.9

bbb[0][3]=2.1

bbb[1][0]=2.2

bbb[1][1]=3.1

bbb[1][2]=1.5

bbb[1][3]=3.2

bbb[2][0]=3.4

bbb[2][1]=2.6

bbb[2][2]=1.2

bbb[2][3]=4.3

matvec product of a and b 

c[0]=28.56

c[1]=20.99

c[2]=20.62

simeq a*x=b 

x[0]=1.0357315306615

x[1]=0.34500241429261

x[2]=-0.098744567841622

simeqb b=ay 

x[0]=1.0357315306615

x[1]=0.34500241429261

x[2]=-0.098744567841622

d=?b[0]=2.1

d=?b[1]=3.2

d=?b[2]=4.3

inverse a = aa 

aa[0][0]=0.014485755673588

aa[0][1]=-0.55528730082086

aa[0][2]=0.64703042008691

aa[1][0]=-0.1979719942057

aa[1][1]=0.92225977788508

aa[1][2]=-0.50941574118783

aa[2][0]=0.38789634637051

aa[2][1]=-0.42491549975857

aa[2][2]=0.10381458232738

inverse aa = bb should be a

bb[0][0]=1.5

bb[0][1]=2.7

bb[0][2]=3.9

bb[1][0]=2.2

bb[1][1]=3.1

bb[1][2]=1.5

bb[2][0]=3.4

bb[2][1]=2.6

bb[2][2]=1.2

matmul a * aa = cc should be identity

cc[0][0]=1

cc[0][1]=-2.2204460492503E-16

cc[0][2]=0

cc[1][0]=-1.1102230246252E-16

cc[1][1]=1

cc[1][2]=8.3266726846887E-17

cc[2][0]=-5.5511151231258E-17

cc[2][1]=0

cc[2][2]=1

det a = e = -12.426

det aa = ee  =? 1/e -0.08047642040882

matsub(matadd(a,aa),aa) = a 

gg[0][0]=1.5

gg[0][1]=2.7

gg[0][2]=3.9

gg[1][0]=2.2

gg[1][1]=3.1

gg[1][2]=1.5

gg[2][0]=3.4

gg[2][1]=2.6

gg[2][2]=1.2