not a TensorRef == no indexes used
assertIndexesUsed(c)	${fixed} = {fixed}$ ${summed} = {summed}$ ${extra} = {extra}$ GOOD	time: 2.461000ms stack: size: 7 Init Prune Expand Prune Factor Prune Tidy
single TensorRef, fixed
assertIndexesUsed(c'_i', {fixed='_i'})	${{ fixed} _i} = {{ fixed} _i}$ ${summed} = {summed}$ ${extra} = {extra}$ GOOD	time: 5.197000ms stack: size: 7 Init Prune Expand Prune Factor Prune Tidy
assertIndexesUsed(c'_ij', {fixed='_ij'})	${{{ fixed} _i} _j} = {{{ fixed} _i} _j}$ ${summed} = {summed}$ ${extra} = {extra}$ GOOD	time: 3.559000ms stack: size: 7 Init Prune Expand Prune Factor Prune Tidy
assertIndexesUsed(c'^i_jk', {fixed='^i_jk'})	${{{{ fixed} ^i} _j} _k} = {{{{ fixed} ^i} _j} _k}$ ${summed} = {summed}$ ${extra} = {extra}$ GOOD	time: 3.845000ms stack: size: 7 Init Prune Expand Prune Factor Prune Tidy
single TensorRef, summed
assertIndexesUsed(c'^i_i', {summed='^i'})	${fixed} = {fixed}$ ${{ summed} ^i} = {{ summed} ^i}$ ${extra} = {extra}$ GOOD	time: 3.152000ms stack: size: 7 Init Prune Expand Prune Factor Prune Tidy
single TensorRef, mixed
assertIndexesUsed(c'^i_ij', {fixed='_j', summed='^i'})	${{ fixed} _j} = {{ fixed} _j}$ ${{ summed} ^i} = {{ summed} ^i}$ ${extra} = {extra}$ GOOD	time: 3.030000ms stack: size: 7 Init Prune Expand Prune Factor Prune Tidy
mul, fixed * summed
assertIndexesUsed(a'_i' * b'^j_j', {fixed='_i', summed='^j'})	${{ fixed} _i} = {{ fixed} _i}$ ${{ summed} ^j} = {{ summed} ^j}$ ${extra} = {extra}$ GOOD	time: 2.612000ms stack: size: 7 Init Prune Expand Prune Factor Prune Tidy
mul, fixed * fixed => summed
assertIndexesUsed(g'^im' * c'_mjk', {fixed='^i_jk', summed='^m'})	${{{{ fixed} ^i} _j} _k} = {{{{ fixed} ^i} _j} _k}$ ${{ summed} ^m} = {{ summed} ^m}$ ${extra} = {extra}$ GOOD	time: 7.294000ms stack: size: 7 Init Prune Expand Prune Factor Prune Tidy
add, nothing
assertIndexesUsed(a + b)	${fixed} = {fixed}$ ${summed} = {summed}$ ${extra} = {extra}$ GOOD	time: 0.392000ms stack: size: 0
add, fixed
assertIndexesUsed(a'_i' + b'_i', {fixed='_i'})	${{ fixed} _i} = {{ fixed} _i}$ ${summed} = {summed}$ ${extra} = {extra}$ GOOD	time: 2.032000ms stack: size: 7 Init Prune Expand Prune Factor Prune Tidy
assertIndexesUsed(a'_ij' + b'_ij', {fixed='_ij'})	${{{ fixed} _i} _j} = {{{ fixed} _i} _j}$ ${summed} = {summed}$ ${extra} = {extra}$ GOOD	time: 3.255000ms stack: size: 7 Init Prune Expand Prune Factor Prune Tidy
add, summed
assertIndexesUsed(a'^i_i' + b'^i_i', {summed='^i'})	${fixed} = {fixed}$ ${{ summed} ^i} = {{ summed} ^i}$ ${extra} = {extra}$ GOOD	time: 2.185000ms stack: size: 7 Init Prune Expand Prune Factor Prune Tidy
assertIndexesUsed(a'^i_i' + b'^j_j', {summed='^ij'})	${fixed} = {fixed}$ ${{{ summed} ^i} ^j} = {{{ summed} ^i} ^j}$ ${extra} = {extra}$ GOOD	time: 3.853000ms stack: size: 7 Init Prune Expand Prune Factor Prune Tidy
add, extra
assertIndexesUsed( a'_i' + b, {extra='_i'})	${fixed} = {fixed}$ ${summed} = {summed}$ ${{ extra} _i} = {{ extra} _i}$ GOOD	time: 2.355000ms stack: size: 7 Init Prune Expand Prune Factor Prune Tidy
assertIndexesUsed( a + b'_j', {extra='_j'})	${fixed} = {fixed}$ ${summed} = {summed}$ ${{ extra} _j} = {{ extra} _j}$ GOOD	time: 2.026000ms stack: size: 7 Init Prune Expand Prune Factor Prune Tidy
assertIndexesUsed( a'_i' + b'_j', {extra='_ij'})	${fixed} = {fixed}$ ${summed} = {summed}$ ${{{ extra} _i} _j} = {{{ extra} _i} _j}$ GOOD	time: 2.184000ms stack: size: 7 Init Prune Expand Prune Factor Prune Tidy
add, fixed + summed
assertIndexesUsed( a'^i_ij' + b'^i_ij', {fixed='_j', summed='^i'})	${{ fixed} _j} = {{ fixed} _j}$ ${{ summed} ^i} = {{ summed} ^i}$ ${extra} = {extra}$ GOOD	time: 3.219000ms stack: size: 7 Init Prune Expand Prune Factor Prune Tidy
assertIndexesUsed( a'^i_ij' + b'^k_kj', {fixed='_j', summed='^ik'})	${{ fixed} _j} = {{ fixed} _j}$ ${{{ summed} ^i} ^k} = {{{ summed} ^i} ^k}$ ${extra} = {extra}$ GOOD	time: 3.543000ms stack: size: 7 Init Prune Expand Prune Factor Prune Tidy
add, fixed + extra
assertIndexesUsed( a'_ij' + b'_kj', {fixed='_j', extra='_ik'})	${{ fixed} _j} = {{ fixed} _j}$ ${summed} = {summed}$ ${{{ extra} _i} _k} = {{{ extra} _i} _k}$ GOOD	time: 3.088000ms stack: size: 7 Init Prune Expand Prune Factor Prune Tidy
add, summed + extra
assertIndexesUsed( a'^i_ij' + b'^i_ik', {summed='^i', extra='_jk'})	${fixed} = {fixed}$ ${{ summed} ^i} = {{ summed} ^i}$ ${{{ extra} _j} _k} = {{{ extra} _j} _k}$ GOOD	time: 4.456000ms stack: size: 7 Init Prune Expand Prune Factor Prune Tidy
add, fixed + summed + extra
assertIndexesUsed( a'_ij^jk' + b'_ij^jl', {fixed='_i', summed='_j', extra='^kl'})	${{ fixed} _i} = {{ fixed} _i}$ ${{ summed} _j} = {{ summed} _j}$ ${{{ extra} ^k} ^l} = {{{ extra} ^k} ^l}$ GOOD	time: 6.256000ms stack: size: 7 Init Prune Expand Prune Factor Prune Tidy
TODO fixed and summed of add
TODO fixed and summed of add and mul
notice that the summed index is counted by the number of the symbol's occurrence, regardless of the lower/upper
this means the lower/upper of the summed will be arbitrary
assertIndexesUsed( a'^i' * b'_i' * c'_j', {fixed='_j', summed='^i'})	${{ fixed} _j} = {{ fixed} _j}$ ${{ summed} ^i} = {{ summed} ^i}$ ${extra} = {extra}$ GOOD	time: 4.291000ms stack: size: 7 Init Prune Expand Prune Factor Prune Tidy
assertIndexesUsed(a'^i' * b'_i' * c'_j' + d'^i' * e'_i' * f'_j', {fixed='_j', summed='^i'})	${{ fixed} _j} = {{ fixed} _j}$ ${{ summed} ^i} = {{ summed} ^i}$ ${extra} = {extra}$ GOOD	time: 4.838000ms stack: size: 7 Init Prune Expand Prune Factor Prune Tidy
assertIndexesUsed(a'^i' * b'_i', {summed='^i'})	${fixed} = {fixed}$ ${{ summed} ^i} = {{ summed} ^i}$ ${extra} = {extra}$ GOOD	time: 1.866000ms stack: size: 7 Init Prune Expand Prune Factor Prune Tidy
assertIndexesUsed(a'^i' * b'_i' + c, {summed='^i'})	${fixed} = {fixed}$ ${{ summed} ^i} = {{ summed} ^i}$ ${extra} = {extra}$ GOOD	time: 1.381000ms stack: size: 7 Init Prune Expand Prune Factor Prune Tidy
assertIndexesUsed(a'^i' * b'_i' + c'^i' * d'_i', {summed='^i'})	${fixed} = {fixed}$ ${{ summed} ^i} = {{ summed} ^i}$ ${extra} = {extra}$ GOOD	time: 1.650000ms stack: size: 7 Init Prune Expand Prune Factor Prune Tidy