diff --git a/ldsc_polyfun/irwls.py b/ldsc_polyfun/irwls.py
index e0c155d..b3dcaeb 100644
--- a/ldsc_polyfun/irwls.py
+++ b/ldsc_polyfun/irwls.py
@@ -125,7 +125,7 @@ def irwls(cls, x, y, update_func, n_blocks, w, slow=False, separators=None):
                 x, y, n_blocks, separators=separators)
         else:
             jknife = jk.LstsqJackknifeFast(
-                x, y, n_blocks, separators=separators)
+                x, y, n_blocks=n_blocks, separators=separators)
 
         return jknife
 
diff --git a/ldsc_polyfun/jackknife.py b/ldsc_polyfun/jackknife.py
index fd1e8fb..2abe7d8 100644
--- a/ldsc_polyfun/jackknife.py
+++ b/ldsc_polyfun/jackknife.py
@@ -254,7 +254,7 @@ def delete_values(cls, x, y, func, s):
         return np.concatenate(d, axis=0)
         
     
-    def __init__(self, x, y, is_large_chi2, n_blocks=None, nn=False, separators=None, chr_num=None, evenodd_split=False, nnls_exact=False):
+    def __init__(self, x, y, is_large_chi2=False, n_blocks=None, nn=False, separators=None, chr_num=None, evenodd_split=False, nnls_exact=False):
     
         Jackknife.__init__(self, x, y, n_blocks, separators)
     
@@ -323,7 +323,7 @@ def __init__(self, x, y, is_large_chi2, n_blocks=None, nn=False, separators=None
         
 class LstsqJackknifeFast(Jackknife):
     
-    def __init__(self, x, y, is_large_chi2, n_blocks=None, separators=None, chr_num=None, evenodd_split=False):
+    def __init__(self, x, y, is_large_chi2=False, n_blocks=None, separators=None, chr_num=None, evenodd_split=False):
     
         #compute jackknife estimates using all SNPs
         Jackknife.__init__(self, x, y, n_blocks, separators)