add parameter set and get functions for lpi (#965)

* add parameter set and get functions for lpi

* remove some unavailbale set and get functions

* add comments and assertation for lp test

* change function order

* remove parameter tests and add isFeasPositive

---------

Co-authored-by: lidingxu <lidingxu.zz@gmail.com>

Author: lidingxu

CHANGELOG.md

@@ -3,6 +3,8 @@
 ## Unreleased
 ### Added
 - Added getLinearConsIndicator
+- Added SCIP_LPPARAM, setIntParam, setRealParam, getIntParam, getRealParam for lpi
+- Added isFeasPositive
 ### Fixed
 ### Changed
 ### Removed

src/pyscipopt/__init__.py

@@ -26,6 +26,7 @@
 from pyscipopt.scip      import Reader
 from pyscipopt.scip      import Sepa
 from pyscipopt.scip      import LP
+from pyscipopt.scip      import PY_SCIP_LPPARAM as SCIP_LPPARAM
 from pyscipopt.scip      import readStatistics
 from pyscipopt.scip      import Expr
 from pyscipopt.scip      import MatrixExpr

src/pyscipopt/lp.pxi

@@ -476,3 +476,77 @@ cdef class LP:
         free(c_binds)
 
         return binds
+
+    # Parameter Methods
+
+    def setIntParam(self, param, value):
+        """
+        Set an int-valued parameter.
+        If the parameter is not supported by the LP solver, KeyError will be raised.
+
+        Parameters
+        ----------
+        param : SCIP_LPPARAM
+            name of parameter
+        value : int
+            value of parameter
+
+        """
+        PY_SCIP_CALL(SCIPlpiSetIntpar(self.lpi, param, value))
+
+    def setRealParam(self, param, value):
+        """
+        Set a real-valued parameter.
+        If the parameter is not supported by the LP solver, KeyError will be raised.
+
+        Parameters
+        ----------
+        param : SCIP_LPPARAM
+            name of parameter
+        value : float
+            value of parameter
+
+        """
+        PY_SCIP_CALL(SCIPlpiSetRealpar(self.lpi, param, value))
+
+    def getIntParam(self, param):
+        """
+        Get the value of a parameter of type int.
+        If the parameter is not supported by the LP solver, KeyError will be raised.
+
+        Parameters
+        ----------
+        param : SCIP_LPPARAM
+            name of parameter
+
+        Returns
+        -------
+        int
+
+        """
+        cdef int value
+
+        PY_SCIP_CALL(SCIPlpiGetIntpar(self.lpi, param, &value))
+
+        return value
+
+    def getRealParam(self, param):
+        """
+        Get the value of a parameter of type float.
+        If the parameter is not supported by the LP solver, KeyError will be raised.
+
+        Parameters
+        ----------
+        param : SCIP_LPPARAM
+            name of parameter
+
+        Returns
+        -------
+        float
+
+        """
+        cdef SCIP_Real value
+
+        PY_SCIP_CALL(SCIPlpiGetRealpar(self.lpi, param, &value))
+
+        return value