fix bugs

Author: geoffroyleconte

src/presolve/postsolve_utils.jl

@@ -0,0 +1,21 @@
+function restore_ilow_iupp!(ilow, iupp, ifix)
+  c_fix = 1
+  nfix = length(ifix)
+
+  nlow = length(ilow)
+  for i in 1:nlow
+    while c_fix ≤ nfix && ilow[i] ≤ ifix[c_fix]
+      c_fix += 1
+    end
+    ilow[i] += c_fix - 1
+  end
+
+  c_fix = 1
+  nupp = length(iupp)
+  for i in 1:nupp
+    while c_fix ≤ nfix && iupp[i] ≤ ifix[c_fix]
+      c_fix += 1
+    end
+    iupp[i] += c_fix - 1
+  end
+end

src/presolve/presolve.jl

@@ -1,6 +1,7 @@
 include("remove_ifix.jl")
 include("empty_rows.jl")
 include("singleton_rows.jl")
+include("postsolve_utils.jl")
 
 mutable struct PresolvedData{T, S}
   ifix::Vector{Int}
@@ -171,13 +172,21 @@ function postsolve!(
   x_out::S,
   y_in::S,
   y_out::S,
+  s_l::SparseVector{T, Int},
+  s_u::SparseVector{T, Int},
 ) where {T, S}
-  if length(psqm.psd.ifix) > 0
-    restore_ifix!(psqm.psd.ifix, psqm.psd.xrm, x_in, x_out)
+  ifix = psqm.psd.ifix
+  if length(ifix) > 0
+    restore_ifix!(ifix, psqm.psd.xrm, x_in, x_out)
   else
     x_out .= @views x_in[1:(qm.meta.nvar)]
   end
   ncon = length(y_out)
   restore_y!(y_in, y_out, psqm.psd.row_cnt, ncon)
 
+  ilow, iupp = s_l.nzind, s_u.nzind
+  restore_ilow_iupp!(ilow, iupp, ifix)
+  s_l_out = SparseVector(qm.meta.nvar, ilow, s_l.nzval)
+  s_u_out = SparseVector(qm.meta.nvar, iupp, s_u.nzval)
+  return s_l_out, s_u_out
 end

src/presolve/remove_ifix.jl

@@ -89,12 +89,12 @@ function remove_ifix!(
 
     # remove ifix in A cols
     Awritepos = 1
-    currentAn = nvar - idxfix + 1  # remove rows if uplo == :U 
     k = 1
-    while k <= Annz && Acols[k] <= currentAn
+    Arm_tmp = 0
+    while k <= Annz - Arm
       Ai, Aj, Ax = Arows[k], Acols[k], Avals[k]
       if Aj == newcurrentifix
-        Arm += 1
+        Arm_tmp += 1
         lcon[Ai] -= Ax * xifix
         ucon[Ai] -= Ax * xifix
       else
@@ -105,6 +105,7 @@ function remove_ifix!(
       end
       k += 1
     end
+    Arm += Arm_tmp
 
     # update c0 with c[currentifix] coeff
     c0_offset += c[currentifix] * xifix

src/presolve/singleton_rows.jl

@@ -3,7 +3,7 @@ removed_singleton_rows(row_cnt::Vector{Int}) = findall(isequal(1), row_cnt)
 function singleton_rows!(Arows, Acols, Avals, lcon::Vector{T}, ucon::Vector{T}, lvar, uvar,
                          nvar, ncon, row_cnt::Vector{Int}, 
                          singl_rows::Vector{Int}) where {T}
-                         
+
   # assume Acols is sorted
   Annz = length(Arows)
   nsingl = length(singl_rows)
@@ -17,18 +17,17 @@ function singleton_rows!(Arows, Acols, Avals, lcon::Vector{T}, ucon::Vector{T},
 
     # remove singleton rows in A rows
     Awritepos = 1
-    currentAn = nvar - idxsingl + 1 
     k = 1
     while k <= Annz - idxsingl + 1
       Ai, Aj, Ax = Arows[k], Acols[k], Avals[k]
       if Ai == newcurrentisingl
-        oldAi = Ai + idxsingl - 1
+        # oldAi = Ai + idxsingl - 1
         if Ax > zero(T)
-          lvar[Aj] = max(lvar[Aj], lcon[oldAi] / Ax)
-          uvar[Aj] = min(uvar[Aj], ucon[oldAi] / Ax)
+          lvar[Aj] = max(lvar[Aj], lcon[currentisingl] / Ax)
+          uvar[Aj] = min(uvar[Aj], ucon[currentisingl] / Ax)
         elseif Ax < zero(T)
-          lvar[Aj] = max(lvar[Aj], ucon[oldAi] / Ax)
-          uvar[Aj] = min(uvar[Aj], lcon[oldAi] / Ax)
+          lvar[Aj] = max(lvar[Aj], ucon[currentisingl] / Ax)
+          uvar[Aj] = min(uvar[Aj], lcon[currentisingl] / Ax)
         else
           error("remove explicit zeros in A")
         end